text: /*
  ** 2001-09-15
  **
  ** The author disclaims copyright to this source code.  In place of
  ** a legal notice, here is a blessing:
  **
  **    May you do good and not evil.
  **    May you find forgiveness for yourself and forgive others.
  **    May you share freely, never taking more than you give.
  **
  *************************************************************************
  ** This header file defines the interface that the SQLite library
  ** presents to client programs.  If a C-function, structure, datatype,
  ** or constant definition does not appear in this file, then it is
  ** not a published API of SQLite, is subject to change without
  ** notice, and should not be referenced by programs that use SQLite.
  **
  ** Some of the definitions that are in this file are marked as
  ** "experimental".  Experimental interfaces are normally new
  ** features recently added to SQLite.  We do not anticipate changes
  ** to experimental interfaces but reserve the right to make minor changes
  ** if experience from use "in the wild" suggest such changes are prudent.
  **
  ** The official C-language API documentation for SQLite is derived
  ** from comments in this file.  This file is the authoritative source
  ** on how SQLite interfaces are supposed to operate.
  **
  ** The name of this file under configuration management is "sqlite.h.in".
  ** The makefile makes some minor changes to this file (such as inserting
  ** the version number) and changes its name to "sqlite3.h" as
  ** part of the build process.
  */
  #ifndef SQLITE3_H
  #define SQLITE3_H
  #include <stdarg.h>     /* Needed for the definition of va_list */
  
  /*
  ** Make sure we can call this stuff from C++.
  */
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  
  /*
  ** Provide the ability to override linkage features of the interface.
  */
  #ifndef SQLITE_EXTERN
  # define SQLITE_EXTERN extern
  #endif
  #ifndef SQLITE_API
  # define SQLITE_API
  #endif
  #ifndef SQLITE_CDECL
  # define SQLITE_CDECL
  #endif
  #ifndef SQLITE_APICALL
  # define SQLITE_APICALL
  #endif
  #ifndef SQLITE_STDCALL
  # define SQLITE_STDCALL SQLITE_APICALL
  #endif
  #ifndef SQLITE_CALLBACK
  # define SQLITE_CALLBACK
  #endif
  #ifndef SQLITE_SYSAPI
  # define SQLITE_SYSAPI
  #endif
  
  /*
  ** These no-op macros are used in front of interfaces to mark those
  ** interfaces as either deprecated or experimental.  New applications
  ** should not use deprecated interfaces - they are supported for backwards
  ** compatibility only.  Application writers should be aware that
  ** experimental interfaces are subject to change in point releases.
  **
  ** These macros used to resolve to various kinds of compiler magic that
  ** would generate warning messages when they were used.  But that
  ** compiler magic ended up generating such a flurry of bug reports
  ** that we have taken it all out and gone back to using simple
  ** noop macros.
  */
  #define SQLITE_DEPRECATED
  #define SQLITE_EXPERIMENTAL
  
  /*
  ** Ensure these symbols were not defined by some previous header file.
  */
  #ifdef SQLITE_VERSION
  # undef SQLITE_VERSION
  #endif
  #ifdef SQLITE_VERSION_NUMBER
  # undef SQLITE_VERSION_NUMBER
  #endif
  
  /*
  ** CAPI3REF: Compile-Time Library Version Numbers
  **
  ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
  ** evaluates to a string literal that is the SQLite version in the
  ** format "X.Y.Z" where X is the major version number (always 3 for
  ** SQLite3) and Y is the minor version number and Z is the release number.)^
  ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
  ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
  ** numbers used in [SQLITE_VERSION].)^
  ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
  ** be larger than the release from which it is derived.  Either Y will
  ** be held constant and Z will be incremented or else Y will be incremented
  ** and Z will be reset to zero.
  **
  ** Since [version 3.6.18] ([dateof:3.6.18]),
  ** SQLite source code has been stored in the
  ** <a href="http://www.fossil-scm.org/">Fossil configuration management
  ** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
  ** a string which identifies a particular check-in of SQLite
  ** within its configuration management system.  ^The SQLITE_SOURCE_ID
  ** string contains the date and time of the check-in (UTC) and a SHA1
  ** or SHA3-256 hash of the entire source tree.  If the source code has
  ** been edited in any way since it was last checked in, then the last
  ** four hexadecimal digits of the hash may be modified.
  **
  ** See also: [sqlite3_libversion()],
  ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
  ** [sqlite_version()] and [sqlite_source_id()].
  */
  #define SQLITE_VERSION        "3.34.1"
  #define SQLITE_VERSION_NUMBER 3034001
  #define SQLITE_SOURCE_ID      "2021-01-20 14:10:07 10e20c0b43500cfb9bbc0eaa061c57514f715d87238f4d835880cd846b9ebd1f"
  
  /*
  ** CAPI3REF: Run-Time Library Version Numbers
  ** KEYWORDS: sqlite3_version sqlite3_sourceid
  **
  ** These interfaces provide the same information as the [SQLITE_VERSION],
  ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
  ** but are associated with the library instead of the header file.  ^(Cautious
  ** programmers might include assert() statements in their application to
  ** verify that values returned by these interfaces match the macros in
  ** the header, and thus ensure that the application is
  ** compiled with matching library and header files.
  **
  ** <blockquote><pre>
  ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
  ** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
  ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
  ** </pre></blockquote>)^
  **
  ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
  ** macro.  ^The sqlite3_libversion() function returns a pointer to the
  ** to the sqlite3_version[] string constant.  The sqlite3_libversion()
  ** function is provided for use in DLLs since DLL users usually do not have
  ** direct access to string constants within the DLL.  ^The
  ** sqlite3_libversion_number() function returns an integer equal to
  ** [SQLITE_VERSION_NUMBER].  ^(The sqlite3_sourceid() function returns
  ** a pointer to a string constant whose value is the same as the
  ** [SQLITE_SOURCE_ID] C preprocessor macro.  Except if SQLite is built
  ** using an edited copy of [the amalgamation], then the last four characters
  ** of the hash might be different from [SQLITE_SOURCE_ID].)^
  **
  ** See also: [sqlite_version()] and [sqlite_source_id()].
  */
  SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
  SQLITE_API const char *sqlite3_libversion(void);
  SQLITE_API const char *sqlite3_sourceid(void);
  SQLITE_API int sqlite3_libversion_number(void);
  
  /*
  ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
  **
  ** ^The sqlite3_compileoption_used() function returns 0 or 1
  ** indicating whether the specified option was defined at
  ** compile time.  ^The SQLITE_ prefix may be omitted from the
  ** option name passed to sqlite3_compileoption_used().
  **
  ** ^The sqlite3_compileoption_get() function allows iterating
  ** over the list of options that were defined at compile time by
  ** returning the N-th compile time option string.  ^If N is out of range,
  ** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
  ** prefix is omitted from any strings returned by
  ** sqlite3_compileoption_get().
  **
  ** ^Support for the diagnostic functions sqlite3_compileoption_used()
  ** and sqlite3_compileoption_get() may be omitted by specifying the
  ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
  **
  ** See also: SQL functions [sqlite_compileoption_used()] and
  ** [sqlite_compileoption_get()] and the [compile_options pragma].
  */
  #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
  SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
  SQLITE_API const char *sqlite3_compileoption_get(int N);
  #else
  # define sqlite3_compileoption_used(X) 0
  # define sqlite3_compileoption_get(X)  ((void*)0)
  #endif
  
  /*
  ** CAPI3REF: Test To See If The Library Is Threadsafe
  **
  ** ^The sqlite3_threadsafe() function returns zero if and only if
  ** SQLite was compiled with mutexing code omitted due to the
  ** [SQLITE_THREADSAFE] compile-time option being set to 0.
  **
  ** SQLite can be compiled with or without mutexes.  When
  ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
  ** are enabled and SQLite is threadsafe.  When the
  ** [SQLITE_THREADSAFE] macro is 0,
  ** the mutexes are omitted.  Without the mutexes, it is not safe
  ** to use SQLite concurrently from more than one thread.
  **
  ** Enabling mutexes incurs a measurable performance penalty.
  ** So if speed is of utmost importance, it makes sense to disable
  ** the mutexes.  But for maximum safety, mutexes should be enabled.
  ** ^The default behavior is for mutexes to be enabled.
  **
  ** This interface can be used by an application to make sure that the
  ** version of SQLite that it is linking against was compiled with
  ** the desired setting of the [SQLITE_THREADSAFE] macro.
  **
  ** This interface only reports on the compile-time mutex setting
  ** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
  ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
  ** can be fully or partially disabled using a call to [sqlite3_config()]
  ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
  ** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
  ** sqlite3_threadsafe() function shows only the compile-time setting of
  ** thread safety, not any run-time changes to that setting made by
  ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
  ** is unchanged by calls to sqlite3_config().)^
  **
  ** See the [threading mode] documentation for additional information.
  */
  SQLITE_API int sqlite3_threadsafe(void);
  
  /*
  ** CAPI3REF: Database Connection Handle
  ** KEYWORDS: {database connection} {database connections}
  **
  ** Each open SQLite database is represented by a pointer to an instance of
  ** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
  ** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
  ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
  ** and [sqlite3_close_v2()] are its destructors.  There are many other
  ** interfaces (such as
  ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
  ** [sqlite3_busy_timeout()] to name but three) that are methods on an
  ** sqlite3 object.
  */
  typedef struct sqlite3 sqlite3;
  
  /*
  ** CAPI3REF: 64-Bit Integer Types
  ** KEYWORDS: sqlite_int64 sqlite_uint64
  **
  ** Because there is no cross-platform way to specify 64-bit integer types
  ** SQLite includes typedefs for 64-bit signed and unsigned integers.
  **
  ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
  ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
  ** compatibility only.
  **
  ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
  ** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
  ** sqlite3_uint64 and sqlite_uint64 types can store integer values
  ** between 0 and +18446744073709551615 inclusive.
  */
  #ifdef SQLITE_INT64_TYPE
    typedef SQLITE_INT64_TYPE sqlite_int64;
  # ifdef SQLITE_UINT64_TYPE
      typedef SQLITE_UINT64_TYPE sqlite_uint64;
  # else
      typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
  # endif
  #elif defined(_MSC_VER) || defined(__BORLANDC__)
    typedef __int64 sqlite_int64;
    typedef unsigned __int64 sqlite_uint64;
  #else
    typedef long long int sqlite_int64;
    typedef unsigned long long int sqlite_uint64;
  #endif
  typedef sqlite_int64 sqlite3_int64;
  typedef sqlite_uint64 sqlite3_uint64;
  
  /*
  ** If compiling for a processor that lacks floating point support,
  ** substitute integer for floating-point.
  */
  #ifdef SQLITE_OMIT_FLOATING_POINT
  # define double sqlite3_int64
  #endif
  
  /*
  ** CAPI3REF: Closing A Database Connection
  ** DESTRUCTOR: sqlite3
  **
  ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
  ** for the [sqlite3] object.
  ** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
  ** the [sqlite3] object is successfully destroyed and all associated
  ** resources are deallocated.
  **
  ** Ideally, applications should [sqlite3_finalize | finalize] all
  ** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and
  ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
  ** with the [sqlite3] object prior to attempting to close the object.
  ** ^If the database connection is associated with unfinalized prepared
  ** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then
  ** sqlite3_close() will leave the database connection open and return
  ** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared
  ** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups,
  ** it returns [SQLITE_OK] regardless, but instead of deallocating the database
  ** connection immediately, it marks the database connection as an unusable
  ** "zombie" and makes arrangements to automatically deallocate the database
  ** connection after all prepared statements are finalized, all BLOB handles
  ** are closed, and all backups have finished. The sqlite3_close_v2() interface
  ** is intended for use with host languages that are garbage collected, and
  ** where the order in which destructors are called is arbitrary.
  **
  ** ^If an [sqlite3] object is destroyed while a transaction is open,
  ** the transaction is automatically rolled back.
  **
  ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
  ** must be either a NULL
  ** pointer or an [sqlite3] object pointer obtained
  ** from [sqlite3_open()], [sqlite3_open16()], or
  ** [sqlite3_open_v2()], and not previously closed.
  ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
  ** argument is a harmless no-op.
  */
  SQLITE_API int sqlite3_close(sqlite3*);
  SQLITE_API int sqlite3_close_v2(sqlite3*);
  
  /*
  ** The type for a callback function.
  ** This is legacy and deprecated.  It is included for historical
  ** compatibility and is not documented.
  */
  typedef int (*sqlite3_callback)(void*,int,char**, char**);
  
  /*
  ** CAPI3REF: One-Step Query Execution Interface
  ** METHOD: sqlite3
  **
  ** The sqlite3_exec() interface is a convenience wrapper around
  ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
  ** that allows an application to run multiple statements of SQL
  ** without having to use a lot of C code.
  **
  ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
  ** semicolon-separate SQL statements passed into its 2nd argument,
  ** in the context of the [database connection] passed in as its 1st
  ** argument.  ^If the callback function of the 3rd argument to
  ** sqlite3_exec() is not NULL, then it is invoked for each result row
  ** coming out of the evaluated SQL statements.  ^The 4th argument to
  ** sqlite3_exec() is relayed through to the 1st argument of each
  ** callback invocation.  ^If the callback pointer to sqlite3_exec()
  ** is NULL, then no callback is ever invoked and result rows are
  ** ignored.
  **
  ** ^If an error occurs while evaluating the SQL statements passed into
  ** sqlite3_exec(), then execution of the current statement stops and
  ** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
  ** is not NULL then any error message is written into memory obtained
  ** from [sqlite3_malloc()] and passed back through the 5th parameter.
  ** To avoid memory leaks, the application should invoke [sqlite3_free()]
  ** on error message strings returned through the 5th parameter of
  ** sqlite3_exec() after the error message string is no longer needed.
  ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
  ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
  ** NULL before returning.
  **
  ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
  ** routine returns SQLITE_ABORT without invoking the callback again and
  ** without running any subsequent SQL statements.
  **
  ** ^The 2nd argument to the sqlite3_exec() callback function is the
  ** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
  ** callback is an array of pointers to strings obtained as if from
  ** [sqlite3_column_text()], one for each column.  ^If an element of a
  ** result row is NULL then the corresponding string pointer for the
  ** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
  ** sqlite3_exec() callback is an array of pointers to strings where each
  ** entry represents the name of corresponding result column as obtained
  ** from [sqlite3_column_name()].
  **
  ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
  ** to an empty string, or a pointer that contains only whitespace and/or
  ** SQL comments, then no SQL statements are evaluated and the database
  ** is not changed.
  **
  ** Restrictions:
  **
  ** <ul>
  ** <li> The application must ensure that the 1st parameter to sqlite3_exec()
  **      is a valid and open [database connection].
  ** <li> The application must not close the [database connection] specified by
  **      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
  ** <li> The application must not modify the SQL statement text passed into
  **      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
  ** </ul>
  */
  SQLITE_API int sqlite3_exec(
    sqlite3*,                                  /* An open database */
    const char *sql,                           /* SQL to be evaluated */
    int (*callback)(void*,int,char**,char**),  /* Callback function */
    void *,                                    /* 1st argument to callback */
    char **errmsg                              /* Error msg written here */
  );
  
  /*
  ** CAPI3REF: Result Codes
  ** KEYWORDS: {result code definitions}
  **
  ** Many SQLite functions return an integer result code from the set shown
  ** here in order to indicate success or failure.
  **
  ** New error codes may be added in future versions of SQLite.
  **
  ** See also: [extended result code definitions]
  */
  #define SQLITE_OK           0   /* Successful result */
  /* beginning-of-error-codes */
  #define SQLITE_ERROR        1   /* Generic error */
  #define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
  #define SQLITE_PERM         3   /* Access permission denied */
  #define SQLITE_ABORT        4   /* Callback routine requested an abort */
  #define SQLITE_BUSY         5   /* The database file is locked */
  #define SQLITE_LOCKED       6   /* A table in the database is locked */
  #define SQLITE_NOMEM        7   /* A malloc() failed */
  #define SQLITE_READONLY     8   /* Attempt to write a readonly database */
  #define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
  #define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
  #define SQLITE_CORRUPT     11   /* The database disk image is malformed */
  #define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
  #define SQLITE_FULL        13   /* Insertion failed because database is full */
  #define SQLITE_CANTOPEN    14   /* Unable to open the database file */
  #define SQLITE_PROTOCOL    15   /* Database lock protocol error */
  #define SQLITE_EMPTY       16   /* Internal use only */
  #define SQLITE_SCHEMA      17   /* The database schema changed */
  #define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
  #define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
  #define SQLITE_MISMATCH    20   /* Data type mismatch */
  #define SQLITE_MISUSE      21   /* Library used incorrectly */
  #define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
  #define SQLITE_AUTH        23   /* Authorization denied */
  #define SQLITE_FORMAT      24   /* Not used */
  #define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
  #define SQLITE_NOTADB      26   /* File opened that is not a database file */
  #define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
  #define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
  #define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
  #define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
  /* end-of-error-codes */
  
  /*
  ** CAPI3REF: Extended Result Codes
  ** KEYWORDS: {extended result code definitions}
  **
  ** In its default configuration, SQLite API routines return one of 30 integer
  ** [result codes].  However, experience has shown that many of
  ** these result codes are too coarse-grained.  They do not provide as
  ** much information about problems as programmers might like.  In an effort to
  ** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
  ** and later) include
  ** support for additional result codes that provide more detailed information
  ** about errors. These [extended result codes] are enabled or disabled
  ** on a per database connection basis using the
  ** [sqlite3_extended_result_codes()] API.  Or, the extended code for
  ** the most recent error can be obtained using
  ** [sqlite3_extended_errcode()].
  */
  #define SQLITE_ERROR_MISSING_COLLSEQ   (SQLITE_ERROR | (1<<8))
  #define SQLITE_ERROR_RETRY             (SQLITE_ERROR | (2<<8))
  #define SQLITE_ERROR_SNAPSHOT          (SQLITE_ERROR | (3<<8))
  #define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
  #define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
  #define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
  #define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
  #define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
  #define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
  #define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
  #define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
  #define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
  #define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
  #define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
  #define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
  #define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
  #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
  #define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
  #define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
  #define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
  #define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
  #define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
  #define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
  #define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
  #define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
  #define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
  #define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
  #define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
  #define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
  #define SQLITE_IOERR_VNODE             (SQLITE_IOERR | (27<<8))
  #define SQLITE_IOERR_AUTH              (SQLITE_IOERR | (28<<8))
  #define SQLITE_IOERR_BEGIN_ATOMIC      (SQLITE_IOERR | (29<<8))
  #define SQLITE_IOERR_COMMIT_ATOMIC     (SQLITE_IOERR | (30<<8))
  #define SQLITE_IOERR_ROLLBACK_ATOMIC   (SQLITE_IOERR | (31<<8))
  #define SQLITE_IOERR_DATA              (SQLITE_IOERR | (32<<8))
  #define SQLITE_IOERR_CORRUPTFS         (SQLITE_IOERR | (33<<8))
  #define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
  #define SQLITE_LOCKED_VTAB             (SQLITE_LOCKED |  (2<<8))
  #define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
  #define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
  #define SQLITE_BUSY_TIMEOUT            (SQLITE_BUSY   |  (3<<8))
  #define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
  #define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
  #define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
  #define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
  #define SQLITE_CANTOPEN_DIRTYWAL       (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
  #define SQLITE_CANTOPEN_SYMLINK        (SQLITE_CANTOPEN | (6<<8))
  #define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
  #define SQLITE_CORRUPT_SEQUENCE        (SQLITE_CORRUPT | (2<<8))
  #define SQLITE_CORRUPT_INDEX           (SQLITE_CORRUPT | (3<<8))
  #define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
  #define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
  #define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
  #define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
  #define SQLITE_READONLY_CANTINIT       (SQLITE_READONLY | (5<<8))
  #define SQLITE_READONLY_DIRECTORY      (SQLITE_READONLY | (6<<8))
  #define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
  #define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
  #define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
  #define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
  #define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
  #define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
  #define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
  #define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
  #define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
  #define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
  #define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
  #define SQLITE_CONSTRAINT_PINNED       (SQLITE_CONSTRAINT |(11<<8))
  #define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
  #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
  #define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
  #define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
  #define SQLITE_OK_LOAD_PERMANENTLY     (SQLITE_OK | (1<<8))
  #define SQLITE_OK_SYMLINK              (SQLITE_OK | (2<<8))
  
  /*
  ** CAPI3REF: Flags For File Open Operations
  **
  ** These bit values are intended for use in the
  ** 3rd parameter to the [sqlite3_open_v2()] interface and
  ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
  */
  #define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
  #define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
  #define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
  #define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
  #define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
  #define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
  #define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
  #define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
  #define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
  #define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
  #define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
  #define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
  #define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
  #define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
  #define SQLITE_OPEN_SUPER_JOURNAL    0x00004000  /* VFS only */
  #define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
  #define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
  #define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
  #define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
  #define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
  #define SQLITE_OPEN_NOFOLLOW         0x01000000  /* Ok for sqlite3_open_v2() */
  
  /* Reserved:                         0x00F00000 */
  /* Legacy compatibility: */
  #define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
  
  
  /*
  ** CAPI3REF: Device Characteristics
  **
  ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
  ** object returns an integer which is a vector of these
  ** bit values expressing I/O characteristics of the mass storage
  ** device that holds the file that the [sqlite3_io_methods]
  ** refers to.
  **
  ** The SQLITE_IOCAP_ATOMIC property means that all writes of
  ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
  ** mean that writes of blocks that are nnn bytes in size and
  ** are aligned to an address which is an integer multiple of
  ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
  ** that when data is appended to a file, the data is appended
  ** first then the size of the file is extended, never the other
  ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
  ** information is written to disk in the same order as calls
  ** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
  ** after reboot following a crash or power loss, the only bytes in a
  ** file that were written at the application level might have changed
  ** and that adjacent bytes, even bytes within the same sector are
  ** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
  ** flag indicates that a file cannot be deleted when open.  The
  ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
  ** read-only media and cannot be changed even by processes with
  ** elevated privileges.
  **
  ** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
  ** filesystem supports doing multiple write operations atomically when those
  ** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
  ** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
  */
  #define SQLITE_IOCAP_ATOMIC                 0x00000001
  #define SQLITE_IOCAP_ATOMIC512              0x00000002
  #define SQLITE_IOCAP_ATOMIC1K               0x00000004
  #define SQLITE_IOCAP_ATOMIC2K               0x00000008
  #define SQLITE_IOCAP_ATOMIC4K               0x00000010
  #define SQLITE_IOCAP_ATOMIC8K               0x00000020
  #define SQLITE_IOCAP_ATOMIC16K              0x00000040
  #define SQLITE_IOCAP_ATOMIC32K              0x00000080
  #define SQLITE_IOCAP_ATOMIC64K              0x00000100
  #define SQLITE_IOCAP_SAFE_APPEND            0x00000200
  #define SQLITE_IOCAP_SEQUENTIAL             0x00000400
  #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
  #define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
  #define SQLITE_IOCAP_IMMUTABLE              0x00002000
  #define SQLITE_IOCAP_BATCH_ATOMIC           0x00004000
  
  /*
  ** CAPI3REF: File Locking Levels
  **
  ** SQLite uses one of these integer values as the second
  ** argument to calls it makes to the xLock() and xUnlock() methods
  ** of an [sqlite3_io_methods] object.
  */
  #define SQLITE_LOCK_NONE          0
  #define SQLITE_LOCK_SHARED        1
  #define SQLITE_LOCK_RESERVED      2
  #define SQLITE_LOCK_PENDING       3
  #define SQLITE_LOCK_EXCLUSIVE     4
  
  /*
  ** CAPI3REF: Synchronization Type Flags
  **
  ** When SQLite invokes the xSync() method of an
  ** [sqlite3_io_methods] object it uses a combination of
  ** these integer values as the second argument.
  **
  ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
  ** sync operation only needs to flush data to mass storage.  Inode
  ** information need not be flushed. If the lower four bits of the flag
  ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
  ** If the lower four bits equal SQLITE_SYNC_FULL, that means
  ** to use Mac OS X style fullsync instead of fsync().
  **
  ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
  ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
  ** settings.  The [synchronous pragma] determines when calls to the
  ** xSync VFS method occur and applies uniformly across all platforms.
  ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
  ** energetic or rigorous or forceful the sync operations are and
  ** only make a difference on Mac OSX for the default SQLite code.
  ** (Third-party VFS implementations might also make the distinction
  ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
  ** operating systems natively supported by SQLite, only Mac OSX
  ** cares about the difference.)
  */
  #define SQLITE_SYNC_NORMAL        0x00002
  #define SQLITE_SYNC_FULL          0x00003
  #define SQLITE_SYNC_DATAONLY      0x00010
  
  /*
  ** CAPI3REF: OS Interface Open File Handle
  **
  ** An [sqlite3_file] object represents an open file in the
  ** [sqlite3_vfs | OS interface layer].  Individual OS interface
  ** implementations will
  ** want to subclass this object by appending additional fields
  ** for their own use.  The pMethods entry is a pointer to an
  ** [sqlite3_io_methods] object that defines methods for performing
  ** I/O operations on the open file.
  */
  typedef struct sqlite3_file sqlite3_file;
  struct sqlite3_file {
    const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
  };
  
  /*
  ** CAPI3REF: OS Interface File Virtual Methods Object
  **
  ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
  ** [sqlite3_file] object (or, more commonly, a subclass of the
  ** [sqlite3_file] object) with a pointer to an instance of this object.
  ** This object defines the methods used to perform various operations
  ** against the open file represented by the [sqlite3_file] object.
  **
  ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
  ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
  ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
  ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
  ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
  ** to NULL.
  **
  ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
  ** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
  ** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
  ** flag may be ORed in to indicate that only the data of the file
  ** and not its inode needs to be synced.
  **
  ** The integer values to xLock() and xUnlock() are one of
  ** <ul>
  ** <li> [SQLITE_LOCK_NONE],
  ** <li> [SQLITE_LOCK_SHARED],
  ** <li> [SQLITE_LOCK_RESERVED],
  ** <li> [SQLITE_LOCK_PENDING], or
  ** <li> [SQLITE_LOCK_EXCLUSIVE].
  ** </ul>
  ** xLock() increases the lock. xUnlock() decreases the lock.
  ** The xCheckReservedLock() method checks whether any database connection,
  ** either in this process or in some other process, is holding a RESERVED,
  ** PENDING, or EXCLUSIVE lock on the file.  It returns true
  ** if such a lock exists and false otherwise.
  **
  ** The xFileControl() method is a generic interface that allows custom
  ** VFS implementations to directly control an open file using the
  ** [sqlite3_file_control()] interface.  The second "op" argument is an
  ** integer opcode.  The third argument is a generic pointer intended to
  ** point to a structure that may contain arguments or space in which to
  ** write return values.  Potential uses for xFileControl() might be
  ** functions to enable blocking locks with timeouts, to change the
  ** locking strategy (for example to use dot-file locks), to inquire
  ** about the status of a lock, or to break stale locks.  The SQLite
  ** core reserves all opcodes less than 100 for its own use.
  ** A [file control opcodes | list of opcodes] less than 100 is available.
  ** Applications that define a custom xFileControl method should use opcodes
  ** greater than 100 to avoid conflicts.  VFS implementations should
  ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
  ** recognize.
  **
  ** The xSectorSize() method returns the sector size of the
  ** device that underlies the file.  The sector size is the
  ** minimum write that can be performed without disturbing
  ** other bytes in the file.  The xDeviceCharacteristics()
  ** method returns a bit vector describing behaviors of the
  ** underlying device:
  **
  ** <ul>
  ** <li> [SQLITE_IOCAP_ATOMIC]
  ** <li> [SQLITE_IOCAP_ATOMIC512]
  ** <li> [SQLITE_IOCAP_ATOMIC1K]
  ** <li> [SQLITE_IOCAP_ATOMIC2K]
  ** <li> [SQLITE_IOCAP_ATOMIC4K]
  ** <li> [SQLITE_IOCAP_ATOMIC8K]
  ** <li> [SQLITE_IOCAP_ATOMIC16K]
  ** <li> [SQLITE_IOCAP_ATOMIC32K]
  ** <li> [SQLITE_IOCAP_ATOMIC64K]
  ** <li> [SQLITE_IOCAP_SAFE_APPEND]
  ** <li> [SQLITE_IOCAP_SEQUENTIAL]
  ** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
  ** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
  ** <li> [SQLITE_IOCAP_IMMUTABLE]
  ** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
  ** </ul>
  **
  ** The SQLITE_IOCAP_ATOMIC property means that all writes of
  ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
  ** mean that writes of blocks that are nnn bytes in size and
  ** are aligned to an address which is an integer multiple of
  ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
  ** that when data is appended to a file, the data is appended
  ** first then the size of the file is extended, never the other
  ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
  ** information is written to disk in the same order as calls
  ** to xWrite().
  **
  ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
  ** in the unread portions of the buffer with zeros.  A VFS that
  ** fails to zero-fill short reads might seem to work.  However,
  ** failure to zero-fill short reads will eventually lead to
  ** database corruption.
  */
  typedef struct sqlite3_io_methods sqlite3_io_methods;
  struct sqlite3_io_methods {
    int iVersion;
    int (*xClose)(sqlite3_file*);
    int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
    int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
    int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
    int (*xSync)(sqlite3_file*, int flags);
    int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
    int (*xLock)(sqlite3_file*, int);
    int (*xUnlock)(sqlite3_file*, int);
    int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
    int (*xFileControl)(sqlite3_file*, int op, void *pArg);
    int (*xSectorSize)(sqlite3_file*);
    int (*xDeviceCharacteristics)(sqlite3_file*);
    /* Methods above are valid for version 1 */
    int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
    int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
    void (*xShmBarrier)(sqlite3_file*);
    int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
    /* Methods above are valid for version 2 */
    int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
    int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
    /* Methods above are valid for version 3 */
    /* Additional methods may be added in future releases */
  };
  
  /*
  ** CAPI3REF: Standard File Control Opcodes
  ** KEYWORDS: {file control opcodes} {file control opcode}
  **
  ** These integer constants are opcodes for the xFileControl method
  ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
  ** interface.
  **
  ** <ul>
  ** <li>[[SQLITE_FCNTL_LOCKSTATE]]
  ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
  ** opcode causes the xFileControl method to write the current state of
  ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
  ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
  ** into an integer that the pArg argument points to. This capability
  ** is used during testing and is only available when the SQLITE_TEST
  ** compile-time option is used.
  **
  ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
  ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
  ** layer a hint of how large the database file will grow to be during the
  ** current transaction.  This hint is not guaranteed to be accurate but it
  ** is often close.  The underlying VFS might choose to preallocate database
  ** file space based on this hint in order to help writes to the database
  ** file run faster.
  **
  ** <li>[[SQLITE_FCNTL_SIZE_LIMIT]]
  ** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
  ** implements [sqlite3_deserialize()] to set an upper bound on the size
  ** of the in-memory database.  The argument is a pointer to a [sqlite3_int64].
  ** If the integer pointed to is negative, then it is filled in with the
  ** current limit.  Otherwise the limit is set to the larger of the value
  ** of the integer pointed to and the current database size.  The integer
  ** pointed to is set to the new limit.
  **
  ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
  ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
  ** extends and truncates the database file in chunks of a size specified
  ** by the user. The fourth argument to [sqlite3_file_control()] should
  ** point to an integer (type int) containing the new chunk-size to use
  ** for the nominated database. Allocating database file space in large
  ** chunks (say 1MB at a time), may reduce file-system fragmentation and
  ** improve performance on some systems.
  **
  ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
  ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
  ** to the [sqlite3_file] object associated with a particular database
  ** connection.  See also [SQLITE_FCNTL_JOURNAL_POINTER].
  **
  ** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
  ** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
  ** to the [sqlite3_file] object associated with the journal file (either
  ** the [rollback journal] or the [write-ahead log]) for a particular database
  ** connection.  See also [SQLITE_FCNTL_FILE_POINTER].
  **
  ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
  ** No longer in use.
  **
  ** <li>[[SQLITE_FCNTL_SYNC]]
  ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
  ** sent to the VFS immediately before the xSync method is invoked on a
  ** database file descriptor. Or, if the xSync method is not invoked
  ** because the user has configured SQLite with
  ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
  ** of the xSync method. In most cases, the pointer argument passed with
  ** this file-control is NULL. However, if the database file is being synced
  ** as part of a multi-database commit, the argument points to a nul-terminated
  ** string containing the transactions super-journal file name. VFSes that
  ** do not need this signal should silently ignore this opcode. Applications
  ** should not call [sqlite3_file_control()] with this opcode as doing so may
  ** disrupt the operation of the specialized VFSes that do require it.
  **
  ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
  ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
  ** and sent to the VFS after a transaction has been committed immediately
  ** but before the database is unlocked. VFSes that do not need this signal
  ** should silently ignore this opcode. Applications should not call
  ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
  ** operation of the specialized VFSes that do require it.
  **
  ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
  ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
  ** retry counts and intervals for certain disk I/O operations for the
  ** windows [VFS] in order to provide robustness in the presence of
  ** anti-virus programs.  By default, the windows VFS will retry file read,
  ** file write, and file delete operations up to 10 times, with a delay
  ** of 25 milliseconds before the first retry and with the delay increasing
  ** by an additional 25 milliseconds with each subsequent retry.  This
  ** opcode allows these two values (10 retries and 25 milliseconds of delay)
  ** to be adjusted.  The values are changed for all database connections
  ** within the same process.  The argument is a pointer to an array of two
  ** integers where the first integer is the new retry count and the second
  ** integer is the delay.  If either integer is negative, then the setting
  ** is not changed but instead the prior value of that setting is written
  ** into the array entry, allowing the current retry settings to be
  ** interrogated.  The zDbName parameter is ignored.
  **
  ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
  ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
  ** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
  ** write ahead log ([WAL file]) and shared memory
  ** files used for transaction control
  ** are automatically deleted when the latest connection to the database
  ** closes.  Setting persistent WAL mode causes those files to persist after
  ** close.  Persisting the files is useful when other processes that do not
  ** have write permission on the directory containing the database file want
  ** to read the database file, as the WAL and shared memory files must exist
  ** in order for the database to be readable.  The fourth parameter to
  ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
  ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
  ** WAL mode.  If the integer is -1, then it is overwritten with the current
  ** WAL persistence setting.
  **
  ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
  ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
  ** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
  ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
  ** xDeviceCharacteristics methods. The fourth parameter to
  ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
  ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
  ** mode.  If the integer is -1, then it is overwritten with the current
  ** zero-damage mode setting.
  **
  ** <li>[[SQLITE_FCNTL_OVERWRITE]]
  ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
  ** a write transaction to indicate that, unless it is rolled back for some
  ** reason, the entire database file will be overwritten by the current
  ** transaction. This is used by VACUUM operations.
  **
  ** <li>[[SQLITE_FCNTL_VFSNAME]]
  ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
  ** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
  ** final bottom-level VFS are written into memory obtained from
  ** [sqlite3_malloc()] and the result is stored in the char* variable
  ** that the fourth parameter of [sqlite3_file_control()] points to.
  ** The caller is responsible for freeing the memory when done.  As with
  ** all file-control actions, there is no guarantee that this will actually
  ** do anything.  Callers should initialize the char* variable to a NULL
  ** pointer in case this file-control is not implemented.  This file-control
  ** is intended for diagnostic use only.
  **
  ** <li>[[SQLITE_FCNTL_VFS_POINTER]]
  ** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
  ** [VFSes] currently in use.  ^(The argument X in
  ** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
  ** of type "[sqlite3_vfs] **".  This opcodes will set *X
  ** to a pointer to the top-level VFS.)^
  ** ^When there are multiple VFS shims in the stack, this opcode finds the
  ** upper-most shim only.
  **
  ** <li>[[SQLITE_FCNTL_PRAGMA]]
  ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
  ** file control is sent to the open [sqlite3_file] object corresponding
  ** to the database file to which the pragma statement refers. ^The argument
  ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
  ** pointers to strings (char**) in which the second element of the array
  ** is the name of the pragma and the third element is the argument to the
  ** pragma or NULL if the pragma has no argument.  ^The handler for an
  ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
  ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
  ** or the equivalent and that string will become the result of the pragma or
  ** the error message if the pragma fails. ^If the
  ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
  ** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
  ** file control returns [SQLITE_OK], then the parser assumes that the
  ** VFS has handled the PRAGMA itself and the parser generates a no-op
  ** prepared statement if result string is NULL, or that returns a copy
  ** of the result string if the string is non-NULL.
  ** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
  ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
  ** that the VFS encountered an error while handling the [PRAGMA] and the
  ** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
  ** file control occurs at the beginning of pragma statement analysis and so
  ** it is able to override built-in [PRAGMA] statements.
  **
  ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
  ** ^The [SQLITE_FCNTL_BUSYHANDLER]
  ** file-control may be invoked by SQLite on the database file handle
  ** shortly after it is opened in order to provide a custom VFS with access
  ** to the connection's busy-handler callback. The argument is of type (void**)
  ** - an array of two (void *) values. The first (void *) actually points
  ** to a function of type (int (*)(void *)). In order to invoke the connection's
  ** busy-handler, this function should be invoked with the second (void *) in
  ** the array as the only argument. If it returns non-zero, then the operation
  ** should be retried. If it returns zero, the custom VFS should abandon the
  ** current operation.
  **
  ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
  ** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
  ** to have SQLite generate a
  ** temporary filename using the same algorithm that is followed to generate
  ** temporary filenames for TEMP tables and other internal uses.  The
  ** argument should be a char** which will be filled with the filename
  ** written into memory obtained from [sqlite3_malloc()].  The caller should
  ** invoke [sqlite3_free()] on the result to avoid a memory leak.
  **
  ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
  ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
  ** maximum number of bytes that will be used for memory-mapped I/O.
  ** The argument is a pointer to a value of type sqlite3_int64 that
  ** is an advisory maximum number of bytes in the file to memory map.  The
  ** pointer is overwritten with the old value.  The limit is not changed if
  ** the value originally pointed to is negative, and so the current limit
  ** can be queried by passing in a pointer to a negative number.  This
  ** file-control is used internally to implement [PRAGMA mmap_size].
  **
  ** <li>[[SQLITE_FCNTL_TRACE]]
  ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
  ** to the VFS about what the higher layers of the SQLite stack are doing.
  ** This file control is used by some VFS activity tracing [shims].
  ** The argument is a zero-terminated string.  Higher layers in the
  ** SQLite stack may generate instances of this file control if
  ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
  **
  ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
  ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
  ** pointer to an integer and it writes a boolean into that integer depending
  ** on whether or not the file has been renamed, moved, or deleted since it
  ** was first opened.
  **
  ** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
  ** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
  ** underlying native file handle associated with a file handle.  This file
  ** control interprets its argument as a pointer to a native file handle and
  ** writes the resulting value there.
  **
  ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
  ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
  ** opcode causes the xFileControl method to swap the file handle with the one
  ** pointed to by the pArg argument.  This capability is used during testing
  ** and only needs to be supported when SQLITE_TEST is defined.
  **
  ** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
  ** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
  ** be advantageous to block on the next WAL lock if the lock is not immediately
  ** available.  The WAL subsystem issues this signal during rare
  ** circumstances in order to fix a problem with priority inversion.
  ** Applications should <em>not</em> use this file-control.
  **
  ** <li>[[SQLITE_FCNTL_ZIPVFS]]
  ** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
  ** VFS should return SQLITE_NOTFOUND for this opcode.
  **
  ** <li>[[SQLITE_FCNTL_RBU]]
  ** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
  ** the RBU extension only.  All other VFS should return SQLITE_NOTFOUND for
  ** this opcode.
  **
  ** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
  ** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
  ** the file descriptor is placed in "batch write mode", which
  ** means all subsequent write operations will be deferred and done
  ** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].  Systems
  ** that do not support batch atomic writes will return SQLITE_NOTFOUND.
  ** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
  ** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
  ** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
  ** no VFS interface calls on the same [sqlite3_file] file descriptor
  ** except for calls to the xWrite method and the xFileControl method
  ** with [SQLITE_FCNTL_SIZE_HINT].
  **
  ** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
  ** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
  ** operations since the previous successful call to
  ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
  ** This file control returns [SQLITE_OK] if and only if the writes were
  ** all performed successfully and have been committed to persistent storage.
  ** ^Regardless of whether or not it is successful, this file control takes
  ** the file descriptor out of batch write mode so that all subsequent
  ** write operations are independent.
  ** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
  ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
  **
  ** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
  ** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
  ** operations since the previous successful call to
  ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
  ** ^This file control takes the file descriptor out of batch write mode
  ** so that all subsequent write operations are independent.
  ** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
  ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
  **
  ** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
  ** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
  ** to block for up to M milliseconds before failing when attempting to
  ** obtain a file lock using the xLock or xShmLock methods of the VFS.
  ** The parameter is a pointer to a 32-bit signed integer that contains
  ** the value that M is to be set to. Before returning, the 32-bit signed
  ** integer is overwritten with the previous value of M.
  **
  ** <li>[[SQLITE_FCNTL_DATA_VERSION]]
  ** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
  ** a database file.  The argument is a pointer to a 32-bit unsigned integer.
  ** The "data version" for the pager is written into the pointer.  The
  ** "data version" changes whenever any change occurs to the corresponding
  ** database file, either through SQL statements on the same database
  ** connection or through transactions committed by separate database
  ** connections possibly in other processes. The [sqlite3_total_changes()]
  ** interface can be used to find if any database on the connection has changed,
  ** but that interface responds to changes on TEMP as well as MAIN and does
  ** not provide a mechanism to detect changes to MAIN only.  Also, the
  ** [sqlite3_total_changes()] interface responds to internal changes only and
  ** omits changes made by other database connections.  The
  ** [PRAGMA data_version] command provides a mechanism to detect changes to
  ** a single attached database that occur due to other database connections,
  ** but omits changes implemented by the database connection on which it is
  ** called.  This file control is the only mechanism to detect changes that
  ** happen either internally or externally and that are associated with
  ** a particular attached database.
  **
  ** <li>[[SQLITE_FCNTL_CKPT_START]]
  ** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint
  ** in wal mode before the client starts to copy pages from the wal
  ** file to the database file.
  **
  ** <li>[[SQLITE_FCNTL_CKPT_DONE]]
  ** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint
  ** in wal mode after the client has finished copying pages from the wal
  ** file to the database file, but before the *-shm file is updated to
  ** record the fact that the pages have been checkpointed.
  ** </ul>
  */
  #define SQLITE_FCNTL_LOCKSTATE               1
  #define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
  #define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
  #define SQLITE_FCNTL_LAST_ERRNO              4
  #define SQLITE_FCNTL_SIZE_HINT               5
  #define SQLITE_FCNTL_CHUNK_SIZE              6
  #define SQLITE_FCNTL_FILE_POINTER            7
  #define SQLITE_FCNTL_SYNC_OMITTED            8
  #define SQLITE_FCNTL_WIN32_AV_RETRY          9
  #define SQLITE_FCNTL_PERSIST_WAL            10
  #define SQLITE_FCNTL_OVERWRITE              11
  #define SQLITE_FCNTL_VFSNAME                12
  #define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
  #define SQLITE_FCNTL_PRAGMA                 14
  #define SQLITE_FCNTL_BUSYHANDLER            15
  #define SQLITE_FCNTL_TEMPFILENAME           16
  #define SQLITE_FCNTL_MMAP_SIZE              18
  #define SQLITE_FCNTL_TRACE                  19
  #define SQLITE_FCNTL_HAS_MOVED              20
  #define SQLITE_FCNTL_SYNC                   21
  #define SQLITE_FCNTL_COMMIT_PHASETWO        22
  #define SQLITE_FCNTL_WIN32_SET_HANDLE       23
  #define SQLITE_FCNTL_WAL_BLOCK              24
  #define SQLITE_FCNTL_ZIPVFS                 25
  #define SQLITE_FCNTL_RBU                    26
  #define SQLITE_FCNTL_VFS_POINTER            27
  #define SQLITE_FCNTL_JOURNAL_POINTER        28
  #define SQLITE_FCNTL_WIN32_GET_HANDLE       29
  #define SQLITE_FCNTL_PDB                    30
  #define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE     31
  #define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE    32
  #define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE  33
  #define SQLITE_FCNTL_LOCK_TIMEOUT           34
  #define SQLITE_FCNTL_DATA_VERSION           35
  #define SQLITE_FCNTL_SIZE_LIMIT             36
  #define SQLITE_FCNTL_CKPT_DONE              37
  #define SQLITE_FCNTL_RESERVE_BYTES          38
  #define SQLITE_FCNTL_CKPT_START             39
  
  /* deprecated names */
  #define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
  #define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
  #define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
  
  
  /*
  ** CAPI3REF: Mutex Handle
  **
  ** The mutex module within SQLite defines [sqlite3_mutex] to be an
  ** abstract type for a mutex object.  The SQLite core never looks
  ** at the internal representation of an [sqlite3_mutex].  It only
  ** deals with pointers to the [sqlite3_mutex] object.
  **
  ** Mutexes are created using [sqlite3_mutex_alloc()].
  */
  typedef struct sqlite3_mutex sqlite3_mutex;
  
  /*
  ** CAPI3REF: Loadable Extension Thunk
  **
  ** A pointer to the opaque sqlite3_api_routines structure is passed as
  ** the third parameter to entry points of [loadable extensions].  This
  ** structure must be typedefed in order to work around compiler warnings
  ** on some platforms.
  */
  typedef struct sqlite3_api_routines sqlite3_api_routines;
  
  /*
  ** CAPI3REF: OS Interface Object
  **
  ** An instance of the sqlite3_vfs object defines the interface between
  ** the SQLite core and the underlying operating system.  The "vfs"
  ** in the name of the object stands for "virtual file system".  See
  ** the [VFS | VFS documentation] for further information.
  **
  ** The VFS interface is sometimes extended by adding new methods onto
  ** the end.  Each time such an extension occurs, the iVersion field
  ** is incremented.  The iVersion value started out as 1 in
  ** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
  ** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
  ** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6].  Additional fields
  ** may be appended to the sqlite3_vfs object and the iVersion value
  ** may increase again in future versions of SQLite.
  ** Note that due to an oversight, the structure
  ** of the sqlite3_vfs object changed in the transition from
  ** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
  ** and yet the iVersion field was not increased.
  **
  ** The szOsFile field is the size of the subclassed [sqlite3_file]
  ** structure used by this VFS.  mxPathname is the maximum length of
  ** a pathname in this VFS.
  **
  ** Registered sqlite3_vfs objects are kept on a linked list formed by
  ** the pNext pointer.  The [sqlite3_vfs_register()]
  ** and [sqlite3_vfs_unregister()] interfaces manage this list
  ** in a thread-safe way.  The [sqlite3_vfs_find()] interface
  ** searches the list.  Neither the application code nor the VFS
  ** implementation should use the pNext pointer.
  **
  ** The pNext field is the only field in the sqlite3_vfs
  ** structure that SQLite will ever modify.  SQLite will only access
  ** or modify this field while holding a particular static mutex.
  ** The application should never modify anything within the sqlite3_vfs
  ** object once the object has been registered.
  **
  ** The zName field holds the name of the VFS module.  The name must
  ** be unique across all VFS modules.
  **
  ** [[sqlite3_vfs.xOpen]]
  ** ^SQLite guarantees that the zFilename parameter to xOpen
  ** is either a NULL pointer or string obtained
  ** from xFullPathname() with an optional suffix added.
  ** ^If a suffix is added to the zFilename parameter, it will
  ** consist of a single "-" character followed by no more than
  ** 11 alphanumeric and/or "-" characters.
  ** ^SQLite further guarantees that
  ** the string will be valid and unchanged until xClose() is
  ** called. Because of the previous sentence,
  ** the [sqlite3_file] can safely store a pointer to the
  ** filename if it needs to remember the filename for some reason.
  ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
  ** must invent its own temporary name for the file.  ^Whenever the
  ** xFilename parameter is NULL it will also be the case that the
  ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
  **
  ** The flags argument to xOpen() includes all bits set in
  ** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
  ** or [sqlite3_open16()] is used, then flags includes at least
  ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
  ** If xOpen() opens a file read-only then it sets *pOutFlags to
  ** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
  **
  ** ^(SQLite will also add one of the following flags to the xOpen()
  ** call, depending on the object being opened:
  **
  ** <ul>
  ** <li>  [SQLITE_OPEN_MAIN_DB]
  ** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
  ** <li>  [SQLITE_OPEN_TEMP_DB]
  ** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
  ** <li>  [SQLITE_OPEN_TRANSIENT_DB]
  ** <li>  [SQLITE_OPEN_SUBJOURNAL]
  ** <li>  [SQLITE_OPEN_SUPER_JOURNAL]
  ** <li>  [SQLITE_OPEN_WAL]
  ** </ul>)^
  **
  ** The file I/O implementation can use the object type flags to
  ** change the way it deals with files.  For example, an application
  ** that does not care about crash recovery or rollback might make
  ** the open of a journal file a no-op.  Writes to this journal would
  ** also be no-ops, and any attempt to read the journal would return
  ** SQLITE_IOERR.  Or the implementation might recognize that a database
  ** file will be doing page-aligned sector reads and writes in a random
  ** order and set up its I/O subsystem accordingly.
  **
  ** SQLite might also add one of the following flags to the xOpen method:
  **
  ** <ul>
  ** <li> [SQLITE_OPEN_DELETEONCLOSE]
  ** <li> [SQLITE_OPEN_EXCLUSIVE]
  ** </ul>
  **
  ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
  ** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
  ** will be set for TEMP databases and their journals, transient
  ** databases, and subjournals.
  **
  ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
  ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
  ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
  ** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
  ** SQLITE_OPEN_CREATE, is used to indicate that file should always
  ** be created, and that it is an error if it already exists.
  ** It is <i>not</i> used to indicate the file should be opened
  ** for exclusive access.
  **
  ** ^At least szOsFile bytes of memory are allocated by SQLite
  ** to hold the [sqlite3_file] structure passed as the third
  ** argument to xOpen.  The xOpen method does not have to
  ** allocate the structure; it should just fill it in.  Note that
  ** the xOpen method must set the sqlite3_file.pMethods to either
  ** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
  ** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
  ** element will be valid after xOpen returns regardless of the success
  ** or failure of the xOpen call.
  **
  ** [[sqlite3_vfs.xAccess]]
  ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
  ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
  ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
  ** to test whether a file is at least readable.  The SQLITE_ACCESS_READ
  ** flag is never actually used and is not implemented in the built-in
  ** VFSes of SQLite.  The file is named by the second argument and can be a
  ** directory. The xAccess method returns [SQLITE_OK] on success or some
  ** non-zero error code if there is an I/O error or if the name of
  ** the file given in the second argument is illegal.  If SQLITE_OK
  ** is returned, then non-zero or zero is written into *pResOut to indicate
  ** whether or not the file is accessible.
  **
  ** ^SQLite will always allocate at least mxPathname+1 bytes for the
  ** output buffer xFullPathname.  The exact size of the output buffer
  ** is also passed as a parameter to both  methods. If the output buffer
  ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
  ** handled as a fatal error by SQLite, vfs implementations should endeavor
  ** to prevent this by setting mxPathname to a sufficiently large value.
  **
  ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
  ** interfaces are not strictly a part of the filesystem, but they are
  ** included in the VFS structure for completeness.
  ** The xRandomness() function attempts to return nBytes bytes
  ** of good-quality randomness into zOut.  The return value is
  ** the actual number of bytes of randomness obtained.
  ** The xSleep() method causes the calling thread to sleep for at
  ** least the number of microseconds given.  ^The xCurrentTime()
  ** method returns a Julian Day Number for the current date and time as
  ** a floating point value.
  ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
  ** Day Number multiplied by 86400000 (the number of milliseconds in
  ** a 24-hour day).
  ** ^SQLite will use the xCurrentTimeInt64() method to get the current
  ** date and time if that method is available (if iVersion is 2 or
  ** greater and the function pointer is not NULL) and will fall back
  ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
  **
  ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
  ** are not used by the SQLite core.  These optional interfaces are provided
  ** by some VFSes to facilitate testing of the VFS code. By overriding
  ** system calls with functions under its control, a test program can
  ** simulate faults and error conditions that would otherwise be difficult
  ** or impossible to induce.  The set of system calls that can be overridden
  ** varies from one VFS to another, and from one version of the same VFS to the
  ** next.  Applications that use these interfaces must be prepared for any
  ** or all of these interfaces to be NULL or for their behavior to change
  ** from one release to the next.  Applications must not attempt to access
  ** any of these methods if the iVersion of the VFS is less than 3.
  */
  typedef struct sqlite3_vfs sqlite3_vfs;
  typedef void (*sqlite3_syscall_ptr)(void);
  struct sqlite3_vfs {
    int iVersion;            /* Structure version number (currently 3) */
    int szOsFile;            /* Size of subclassed sqlite3_file */
    int mxPathname;          /* Maximum file pathname length */
    sqlite3_vfs *pNext;      /* Next registered VFS */
    const char *zName;       /* Name of this virtual file system */
    void *pAppData;          /* Pointer to application-specific data */
    int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
                 int flags, int *pOutFlags);
    int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
    int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
    int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
    void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
    void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
    void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
    void (*xDlClose)(sqlite3_vfs*, void*);
    int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
    int (*xSleep)(sqlite3_vfs*, int microseconds);
    int (*xCurrentTime)(sqlite3_vfs*, double*);
    int (*xGetLastError)(sqlite3_vfs*, int, char *);
    /*
    ** The methods above are in version 1 of the sqlite_vfs object
    ** definition.  Those that follow are added in version 2 or later
    */
    int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
    /*
    ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
    ** Those below are for version 3 and greater.
    */
    int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
    sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
    const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
    /*
    ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
    ** New fields may be appended in future versions.  The iVersion
    ** value will increment whenever this happens.
    */
  };
  
  /*
  ** CAPI3REF: Flags for the xAccess VFS method
  **
  ** These integer constants can be used as the third parameter to
  ** the xAccess method of an [sqlite3_vfs] object.  They determine
  ** what kind of permissions the xAccess method is looking for.
  ** With SQLITE_ACCESS_EXISTS, the xAccess method
  ** simply checks whether the file exists.
  ** With SQLITE_ACCESS_READWRITE, the xAccess method
  ** checks whether the named directory is both readable and writable
  ** (in other words, if files can be added, removed, and renamed within
  ** the directory).
  ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
  ** [temp_store_directory pragma], though this could change in a future
  ** release of SQLite.
  ** With SQLITE_ACCESS_READ, the xAccess method
  ** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
  ** currently unused, though it might be used in a future release of
  ** SQLite.
  */
  #define SQLITE_ACCESS_EXISTS    0
  #define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
  #define SQLITE_ACCESS_READ      2   /* Unused */
  
  /*
  ** CAPI3REF: Flags for the xShmLock VFS method
  **
  ** These integer constants define the various locking operations
  ** allowed by the xShmLock method of [sqlite3_io_methods].  The
  ** following are the only legal combinations of flags to the
  ** xShmLock method:
  **
  ** <ul>
  ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
  ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
  ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
  ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
  ** </ul>
  **
  ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
  ** was given on the corresponding lock.
  **
  ** The xShmLock method can transition between unlocked and SHARED or
  ** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
  ** and EXCLUSIVE.
  */
  #define SQLITE_SHM_UNLOCK       1
  #define SQLITE_SHM_LOCK         2
  #define SQLITE_SHM_SHARED       4
  #define SQLITE_SHM_EXCLUSIVE    8
  
  /*
  ** CAPI3REF: Maximum xShmLock index
  **
  ** The xShmLock method on [sqlite3_io_methods] may use values
  ** between 0 and this upper bound as its "offset" argument.
  ** The SQLite core will never attempt to acquire or release a
  ** lock outside of this range
  */
  #define SQLITE_SHM_NLOCK        8
  
  
  /*
  ** CAPI3REF: Initialize The SQLite Library
  **
  ** ^The sqlite3_initialize() routine initializes the
  ** SQLite library.  ^The sqlite3_shutdown() routine
  ** deallocates any resources that were allocated by sqlite3_initialize().
  ** These routines are designed to aid in process initialization and
  ** shutdown on embedded systems.  Workstation applications using
  ** SQLite normally do not need to invoke either of these routines.
  **
  ** A call to sqlite3_initialize() is an "effective" call if it is
  ** the first time sqlite3_initialize() is invoked during the lifetime of
  ** the process, or if it is the first time sqlite3_initialize() is invoked
  ** following a call to sqlite3_shutdown().  ^(Only an effective call
  ** of sqlite3_initialize() does any initialization.  All other calls
  ** are harmless no-ops.)^
  **
  ** A call to sqlite3_shutdown() is an "effective" call if it is the first
  ** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
  ** an effective call to sqlite3_shutdown() does any deinitialization.
  ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
  **
  ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
  ** is not.  The sqlite3_shutdown() interface must only be called from a
  ** single thread.  All open [database connections] must be closed and all
  ** other SQLite resources must be deallocated prior to invoking
  ** sqlite3_shutdown().
  **
  ** Among other things, ^sqlite3_initialize() will invoke
  ** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
  ** will invoke sqlite3_os_end().
  **
  ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
  ** ^If for some reason, sqlite3_initialize() is unable to initialize
  ** the library (perhaps it is unable to allocate a needed resource such
  ** as a mutex) it returns an [error code] other than [SQLITE_OK].
  **
  ** ^The sqlite3_initialize() routine is called internally by many other
  ** SQLite interfaces so that an application usually does not need to
  ** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
  ** calls sqlite3_initialize() so the SQLite library will be automatically
  ** initialized when [sqlite3_open()] is called if it has not be initialized
  ** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
  ** compile-time option, then the automatic calls to sqlite3_initialize()
  ** are omitted and the application must call sqlite3_initialize() directly
  ** prior to using any other SQLite interface.  For maximum portability,
  ** it is recommended that applications always invoke sqlite3_initialize()
  ** directly prior to using any other SQLite interface.  Future releases
  ** of SQLite may require this.  In other words, the behavior exhibited
  ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
  ** default behavior in some future release of SQLite.
  **
  ** The sqlite3_os_init() routine does operating-system specific
  ** initialization of the SQLite library.  The sqlite3_os_end()
  ** routine undoes the effect of sqlite3_os_init().  Typical tasks
  ** performed by these routines include allocation or deallocation
  ** of static resources, initialization of global variables,
  ** setting up a default [sqlite3_vfs] module, or setting up
  ** a default configuration using [sqlite3_config()].
  **
  ** The application should never invoke either sqlite3_os_init()
  ** or sqlite3_os_end() directly.  The application should only invoke
  ** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
  ** interface is called automatically by sqlite3_initialize() and
  ** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
  ** implementations for sqlite3_os_init() and sqlite3_os_end()
  ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
  ** When [custom builds | built for other platforms]
  ** (using the [SQLITE_OS_OTHER=1] compile-time
  ** option) the application must supply a suitable implementation for
  ** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
  ** implementation of sqlite3_os_init() or sqlite3_os_end()
  ** must return [SQLITE_OK] on success and some other [error code] upon
  ** failure.
  */
  SQLITE_API int sqlite3_initialize(void);
  SQLITE_API int sqlite3_shutdown(void);
  SQLITE_API int sqlite3_os_init(void);
  SQLITE_API int sqlite3_os_end(void);
  
  /*
  ** CAPI3REF: Configuring The SQLite Library
  **
  ** The sqlite3_config() interface is used to make global configuration
  ** changes to SQLite in order to tune SQLite to the specific needs of
  ** the application.  The default configuration is recommended for most
  ** applications and so this routine is usually not necessary.  It is
  ** provided to support rare applications with unusual needs.
  **
  ** <b>The sqlite3_config() interface is not threadsafe. The application
  ** must ensure that no other SQLite interfaces are invoked by other
  ** threads while sqlite3_config() is running.</b>
  **
  ** The sqlite3_config() interface
  ** may only be invoked prior to library initialization using
  ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
  ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
  ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
  ** Note, however, that ^sqlite3_config() can be called as part of the
  ** implementation of an application-defined [sqlite3_os_init()].
  **
  ** The first argument to sqlite3_config() is an integer
  ** [configuration option] that determines
  ** what property of SQLite is to be configured.  Subsequent arguments
  ** vary depending on the [configuration option]
  ** in the first argument.
  **
  ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
  ** ^If the option is unknown or SQLite is unable to set the option
  ** then this routine returns a non-zero [error code].
  */
  SQLITE_API int sqlite3_config(int, ...);
  
  /*
  ** CAPI3REF: Configure database connections
  ** METHOD: sqlite3
  **
  ** The sqlite3_db_config() interface is used to make configuration
  ** changes to a [database connection].  The interface is similar to
  ** [sqlite3_config()] except that the changes apply to a single
  ** [database connection] (specified in the first argument).
  **
  ** The second argument to sqlite3_db_config(D,V,...)  is the
  ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
  ** that indicates what aspect of the [database connection] is being configured.
  ** Subsequent arguments vary depending on the configuration verb.
  **
  ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
  ** the call is considered successful.
  */
  SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
  
  /*
  ** CAPI3REF: Memory Allocation Routines
  **
  ** An instance of this object defines the interface between SQLite
  ** and low-level memory allocation routines.
  **
  ** This object is used in only one place in the SQLite interface.
  ** A pointer to an instance of this object is the argument to
  ** [sqlite3_config()] when the configuration option is
  ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
  ** By creating an instance of this object
  ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
  ** during configuration, an application can specify an alternative
  ** memory allocation subsystem for SQLite to use for all of its
  ** dynamic memory needs.
  **
  ** Note that SQLite comes with several [built-in memory allocators]
  ** that are perfectly adequate for the overwhelming majority of applications
  ** and that this object is only useful to a tiny minority of applications
  ** with specialized memory allocation requirements.  This object is
  ** also used during testing of SQLite in order to specify an alternative
  ** memory allocator that simulates memory out-of-memory conditions in
  ** order to verify that SQLite recovers gracefully from such
  ** conditions.
  **
  ** The xMalloc, xRealloc, and xFree methods must work like the
  ** malloc(), realloc() and free() functions from the standard C library.
  ** ^SQLite guarantees that the second argument to
  ** xRealloc is always a value returned by a prior call to xRoundup.
  **
  ** xSize should return the allocated size of a memory allocation
  ** previously obtained from xMalloc or xRealloc.  The allocated size
  ** is always at least as big as the requested size but may be larger.
  **
  ** The xRoundup method returns what would be the allocated size of
  ** a memory allocation given a particular requested size.  Most memory
  ** allocators round up memory allocations at least to the next multiple
  ** of 8.  Some allocators round up to a larger multiple or to a power of 2.
  ** Every memory allocation request coming in through [sqlite3_malloc()]
  ** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
  ** that causes the corresponding memory allocation to fail.
  **
  ** The xInit method initializes the memory allocator.  For example,
  ** it might allocate any required mutexes or initialize internal data
  ** structures.  The xShutdown method is invoked (indirectly) by
  ** [sqlite3_shutdown()] and should deallocate any resources acquired
  ** by xInit.  The pAppData pointer is used as the only parameter to
  ** xInit and xShutdown.
  **
  ** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes
  ** the xInit method, so the xInit method need not be threadsafe.  The
  ** xShutdown method is only called from [sqlite3_shutdown()] so it does
  ** not need to be threadsafe either.  For all other methods, SQLite
  ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
  ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
  ** it is by default) and so the methods are automatically serialized.
  ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
  ** methods must be threadsafe or else make their own arrangements for
  ** serialization.
  **
  ** SQLite will never invoke xInit() more than once without an intervening
  ** call to xShutdown().
  */
  typedef struct sqlite3_mem_methods sqlite3_mem_methods;
  struct sqlite3_mem_methods {
    void *(*xMalloc)(int);         /* Memory allocation function */
    void (*xFree)(void*);          /* Free a prior allocation */
    void *(*xRealloc)(void*,int);  /* Resize an allocation */
    int (*xSize)(void*);           /* Return the size of an allocation */
    int (*xRoundup)(int);          /* Round up request size to allocation size */
    int (*xInit)(void*);           /* Initialize the memory allocator */
    void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
    void *pAppData;                /* Argument to xInit() and xShutdown() */
  };
  
  /*
  ** CAPI3REF: Configuration Options
  ** KEYWORDS: {configuration option}
  **
  ** These constants are the available integer configuration options that
  ** can be passed as the first argument to the [sqlite3_config()] interface.
  **
  ** New configuration options may be added in future releases of SQLite.
  ** Existing configuration options might be discontinued.  Applications
  ** should check the return code from [sqlite3_config()] to make sure that
  ** the call worked.  The [sqlite3_config()] interface will return a
  ** non-zero [error code] if a discontinued or unsupported configuration option
  ** is invoked.
  **
  ** <dl>
  ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
  ** <dd>There are no arguments to this option.  ^This option sets the
  ** [threading mode] to Single-thread.  In other words, it disables
  ** all mutexing and puts SQLite into a mode where it can only be used
  ** by a single thread.   ^If SQLite is compiled with
  ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
  ** it is not possible to change the [threading mode] from its default
  ** value of Single-thread and so [sqlite3_config()] will return
  ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
  ** configuration option.</dd>
  **
  ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
  ** <dd>There are no arguments to this option.  ^This option sets the
  ** [threading mode] to Multi-thread.  In other words, it disables
  ** mutexing on [database connection] and [prepared statement] objects.
  ** The application is responsible for serializing access to
  ** [database connections] and [prepared statements].  But other mutexes
  ** are enabled so that SQLite will be safe to use in a multi-threaded
  ** environment as long as no two threads attempt to use the same
  ** [database connection] at the same time.  ^If SQLite is compiled with
  ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
  ** it is not possible to set the Multi-thread [threading mode] and
  ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
  ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
  **
  ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
  ** <dd>There are no arguments to this option.  ^This option sets the
  ** [threading mode] to Serialized. In other words, this option enables
  ** all mutexes including the recursive
  ** mutexes on [database connection] and [prepared statement] objects.
  ** In this mode (which is the default when SQLite is compiled with
  ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
  ** to [database connections] and [prepared statements] so that the
  ** application is free to use the same [database connection] or the
  ** same [prepared statement] in different threads at the same time.
  ** ^If SQLite is compiled with
  ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
  ** it is not possible to set the Serialized [threading mode] and
  ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
  ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
  **
  ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
  ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
  ** a pointer to an instance of the [sqlite3_mem_methods] structure.
  ** The argument specifies
  ** alternative low-level memory allocation routines to be used in place of
  ** the memory allocation routines built into SQLite.)^ ^SQLite makes
  ** its own private copy of the content of the [sqlite3_mem_methods] structure
  ** before the [sqlite3_config()] call returns.</dd>
  **
  ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
  ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
  ** is a pointer to an instance of the [sqlite3_mem_methods] structure.
  ** The [sqlite3_mem_methods]
  ** structure is filled with the currently defined memory allocation routines.)^
  ** This option can be used to overload the default memory allocation
  ** routines with a wrapper that simulations memory allocation failure or
  ** tracks memory usage, for example. </dd>
  **
  ** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
  ** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
  ** type int, interpreted as a boolean, which if true provides a hint to
  ** SQLite that it should avoid large memory allocations if possible.
  ** SQLite will run faster if it is free to make large memory allocations,
  ** but some application might prefer to run slower in exchange for
  ** guarantees about memory fragmentation that are possible if large
  ** allocations are avoided.  This hint is normally off.
  ** </dd>
  **
  ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
  ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
  ** interpreted as a boolean, which enables or disables the collection of
  ** memory allocation statistics. ^(When memory allocation statistics are
  ** disabled, the following SQLite interfaces become non-operational:
  **   <ul>
  **   <li> [sqlite3_hard_heap_limit64()]
  **   <li> [sqlite3_memory_used()]
  **   <li> [sqlite3_memory_highwater()]
  **   <li> [sqlite3_soft_heap_limit64()]
  **   <li> [sqlite3_status64()]
  **   </ul>)^
  ** ^Memory allocation statistics are enabled by default unless SQLite is
  ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
  ** allocation statistics are disabled by default.
  ** </dd>
  **
  ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
  ** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
  ** </dd>
  **
  ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
  ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
  ** that SQLite can use for the database page cache with the default page
  ** cache implementation.
  ** This configuration option is a no-op if an application-defined page
  ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
  ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
  ** 8-byte aligned memory (pMem), the size of each page cache line (sz),
  ** and the number of cache lines (N).
  ** The sz argument should be the size of the largest database page
  ** (a power of two between 512 and 65536) plus some extra bytes for each
  ** page header.  ^The number of extra bytes needed by the page header
  ** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
  ** ^It is harmless, apart from the wasted memory,
  ** for the sz parameter to be larger than necessary.  The pMem
  ** argument must be either a NULL pointer or a pointer to an 8-byte
  ** aligned block of memory of at least sz*N bytes, otherwise
  ** subsequent behavior is undefined.
  ** ^When pMem is not NULL, SQLite will strive to use the memory provided
  ** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
  ** a page cache line is larger than sz bytes or if all of the pMem buffer
  ** is exhausted.
  ** ^If pMem is NULL and N is non-zero, then each database connection
  ** does an initial bulk allocation for page cache memory
  ** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
  ** of -1024*N bytes if N is negative, . ^If additional
  ** page cache memory is needed beyond what is provided by the initial
  ** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
  ** additional cache line. </dd>
  **
  ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
  ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
  ** that SQLite will use for all of its dynamic memory allocation needs
  ** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
  ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
  ** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
  ** [SQLITE_ERROR] if invoked otherwise.
  ** ^There are three arguments to SQLITE_CONFIG_HEAP:
  ** An 8-byte aligned pointer to the memory,
  ** the number of bytes in the memory buffer, and the minimum allocation size.
  ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
  ** to using its default memory allocator (the system malloc() implementation),
  ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
  ** memory pointer is not NULL then the alternative memory
  ** allocator is engaged to handle all of SQLites memory allocation needs.
  ** The first pointer (the memory pointer) must be aligned to an 8-byte
  ** boundary or subsequent behavior of SQLite will be undefined.
  ** The minimum allocation size is capped at 2**12. Reasonable values
  ** for the minimum allocation size are 2**5 through 2**8.</dd>
  **
  ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
  ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
  ** pointer to an instance of the [sqlite3_mutex_methods] structure.
  ** The argument specifies alternative low-level mutex routines to be used
  ** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
  ** the content of the [sqlite3_mutex_methods] structure before the call to
  ** [sqlite3_config()] returns. ^If SQLite is compiled with
  ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
  ** the entire mutexing subsystem is omitted from the build and hence calls to
  ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
  ** return [SQLITE_ERROR].</dd>
  **
  ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
  ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
  ** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
  ** [sqlite3_mutex_methods]
  ** structure is filled with the currently defined mutex routines.)^
  ** This option can be used to overload the default mutex allocation
  ** routines with a wrapper used to track mutex usage for performance
  ** profiling or testing, for example.   ^If SQLite is compiled with
  ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
  ** the entire mutexing subsystem is omitted from the build and hence calls to
  ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
  ** return [SQLITE_ERROR].</dd>
  **
  ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
  ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
  ** the default size of lookaside memory on each [database connection].
  ** The first argument is the
  ** size of each lookaside buffer slot and the second is the number of
  ** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
  ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
  ** option to [sqlite3_db_config()] can be used to change the lookaside
  ** configuration on individual connections.)^ </dd>
  **
  ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
  ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
  ** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
  ** the interface to a custom page cache implementation.)^
  ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
  **
  ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
  ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
  ** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
  ** the current page cache implementation into that object.)^ </dd>
  **
  ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
  ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
  ** global [error log].
  ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
  ** function with a call signature of void(*)(void*,int,const char*),
  ** and a pointer to void. ^If the function pointer is not NULL, it is
  ** invoked by [sqlite3_log()] to process each logging event.  ^If the
  ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
  ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
  ** passed through as the first parameter to the application-defined logger
  ** function whenever that function is invoked.  ^The second parameter to
  ** the logger function is a copy of the first parameter to the corresponding
  ** [sqlite3_log()] call and is intended to be a [result code] or an
  ** [extended result code].  ^The third parameter passed to the logger is
  ** log message after formatting via [sqlite3_snprintf()].
  ** The SQLite logging interface is not reentrant; the logger function
  ** supplied by the application must not invoke any SQLite interface.
  ** In a multi-threaded application, the application-defined logger
  ** function must be threadsafe. </dd>
  **
  ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
  ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
  ** If non-zero, then URI handling is globally enabled. If the parameter is zero,
  ** then URI handling is globally disabled.)^ ^If URI handling is globally
  ** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
  ** [sqlite3_open16()] or
  ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
  ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
  ** connection is opened. ^If it is globally disabled, filenames are
  ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
  ** database connection is opened. ^(By default, URI handling is globally
  ** disabled. The default value may be changed by compiling with the
  ** [SQLITE_USE_URI] symbol defined.)^
  **
  ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
  ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
  ** argument which is interpreted as a boolean in order to enable or disable
  ** the use of covering indices for full table scans in the query optimizer.
  ** ^The default setting is determined
  ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
  ** if that compile-time option is omitted.
  ** The ability to disable the use of covering indices for full table scans
  ** is because some incorrectly coded legacy applications might malfunction
  ** when the optimization is enabled.  Providing the ability to
  ** disable the optimization allows the older, buggy application code to work
  ** without change even with newer versions of SQLite.
  **
  ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
  ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
  ** <dd> These options are obsolete and should not be used by new code.
  ** They are retained for backwards compatibility but are now no-ops.
  ** </dd>
  **
  ** [[SQLITE_CONFIG_SQLLOG]]
  ** <dt>SQLITE_CONFIG_SQLLOG
  ** <dd>This option is only available if sqlite is compiled with the
  ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
  ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
  ** The second should be of type (void*). The callback is invoked by the library
  ** in three separate circumstances, identified by the value passed as the
  ** fourth parameter. If the fourth parameter is 0, then the database connection
  ** passed as the second argument has just been opened. The third argument
  ** points to a buffer containing the name of the main database file. If the
  ** fourth parameter is 1, then the SQL statement that the third parameter
  ** points to has just been executed. Or, if the fourth parameter is 2, then
  ** the connection being passed as the second parameter is being closed. The
  ** third parameter is passed NULL In this case.  An example of using this
  ** configuration option can be seen in the "test_sqllog.c" source file in
  ** the canonical SQLite source tree.</dd>
  **
  ** [[SQLITE_CONFIG_MMAP_SIZE]]
  ** <dt>SQLITE_CONFIG_MMAP_SIZE
  ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
  ** that are the default mmap size limit (the default setting for
  ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
  ** ^The default setting can be overridden by each database connection using
  ** either the [PRAGMA mmap_size] command, or by using the
  ** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
  ** will be silently truncated if necessary so that it does not exceed the
  ** compile-time maximum mmap size set by the
  ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
  ** ^If either argument to this option is negative, then that argument is
  ** changed to its compile-time default.
  **
  ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
  ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
  ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
  ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
  ** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
  ** that specifies the maximum size of the created heap.
  **
  ** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
  ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
  ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
  ** is a pointer to an integer and writes into that integer the number of extra
  ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
  ** The amount of extra space required can change depending on the compiler,
  ** target platform, and SQLite version.
  **
  ** [[SQLITE_CONFIG_PMASZ]]
  ** <dt>SQLITE_CONFIG_PMASZ
  ** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
  ** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
  ** sorter to that integer.  The default minimum PMA Size is set by the
  ** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
  ** to help with sort operations when multithreaded sorting
  ** is enabled (using the [PRAGMA threads] command) and the amount of content
  ** to be sorted exceeds the page size times the minimum of the
  ** [PRAGMA cache_size] setting and this value.
  **
  ** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
  ** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
  ** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
  ** becomes the [statement journal] spill-to-disk threshold.
  ** [Statement journals] are held in memory until their size (in bytes)
  ** exceeds this threshold, at which point they are written to disk.
  ** Or if the threshold is -1, statement journals are always held
  ** exclusively in memory.
  ** Since many statement journals never become large, setting the spill
  ** threshold to a value such as 64KiB can greatly reduce the amount of
  ** I/O required to support statement rollback.
  ** The default value for this setting is controlled by the
  ** [SQLITE_STMTJRNL_SPILL] compile-time option.
  **
  ** [[SQLITE_CONFIG_SORTERREF_SIZE]]
  ** <dt>SQLITE_CONFIG_SORTERREF_SIZE
  ** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
  ** of type (int) - the new value of the sorter-reference size threshold.
  ** Usually, when SQLite uses an external sort to order records according
  ** to an ORDER BY clause, all fields required by the caller are present in the
  ** sorted records. However, if SQLite determines based on the declared type
  ** of a table column that its values are likely to be very large - larger
  ** than the configured sorter-reference size threshold - then a reference
  ** is stored in each sorted record and the required column values loaded
  ** from the database as records are returned in sorted order. The default
  ** value for this option is to never use this optimization. Specifying a
  ** negative value for this option restores the default behaviour.
  ** This option is only available if SQLite is compiled with the
  ** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
  **
  ** [[SQLITE_CONFIG_MEMDB_MAXSIZE]]
  ** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE
  ** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
  ** [sqlite3_int64] parameter which is the default maximum size for an in-memory
  ** database created using [sqlite3_deserialize()].  This default maximum
  ** size can be adjusted up or down for individual databases using the
  ** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control].  If this
  ** configuration setting is never used, then the default maximum is determined
  ** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option.  If that
  ** compile-time option is not set, then the default maximum is 1073741824.
  ** </dl>
  */
  #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
  #define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
  #define SQLITE_CONFIG_SERIALIZED    3  /* nil */
  #define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
  #define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
  #define SQLITE_CONFIG_SCRATCH       6  /* No longer used */
  #define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
  #define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
  #define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
  #define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
  #define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
  /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
  #define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
  #define SQLITE_CONFIG_PCACHE       14  /* no-op */
  #define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
  #define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
  #define SQLITE_CONFIG_URI          17  /* int */
  #define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
  #define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
  #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
  #define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
  #define SQLITE_CONFIG_MMAP_SIZE    22  /* sqlite3_int64, sqlite3_int64 */
  #define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
  #define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
  #define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
  #define SQLITE_CONFIG_STMTJRNL_SPILL      26  /* int nByte */
  #define SQLITE_CONFIG_SMALL_MALLOC        27  /* boolean */
  #define SQLITE_CONFIG_SORTERREF_SIZE      28  /* int nByte */
  #define SQLITE_CONFIG_MEMDB_MAXSIZE       29  /* sqlite3_int64 */
  
  /*
  ** CAPI3REF: Database Connection Configuration Options
  **
  ** These constants are the available integer configuration options that
  ** can be passed as the second argument to the [sqlite3_db_config()] interface.
  **
  ** New configuration options may be added in future releases of SQLite.
  ** Existing configuration options might be discontinued.  Applications
  ** should check the return code from [sqlite3_db_config()] to make sure that
  ** the call worked.  ^The [sqlite3_db_config()] interface will return a
  ** non-zero [error code] if a discontinued or unsupported configuration option
  ** is invoked.
  **
  ** <dl>
  ** [[SQLITE_DBCONFIG_LOOKASIDE]]
  ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
  ** <dd> ^This option takes three additional arguments that determine the
  ** [lookaside memory allocator] configuration for the [database connection].
  ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
  ** pointer to a memory buffer to use for lookaside memory.
  ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
  ** may be NULL in which case SQLite will allocate the
  ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
  ** size of each lookaside buffer slot.  ^The third argument is the number of
  ** slots.  The size of the buffer in the first argument must be greater than
  ** or equal to the product of the second and third arguments.  The buffer
  ** must be aligned to an 8-byte boundary.  ^If the second argument to
  ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
  ** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
  ** configuration for a database connection can only be changed when that
  ** connection is not currently using lookaside memory, or in other words
  ** when the "current value" returned by
  ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
  ** Any attempt to change the lookaside memory configuration when lookaside
  ** memory is in use leaves the configuration unchanged and returns
  ** [SQLITE_BUSY].)^</dd>
  **
  ** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
  ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
  ** <dd> ^This option is used to enable or disable the enforcement of
  ** [foreign key constraints].  There should be two additional arguments.
  ** The first argument is an integer which is 0 to disable FK enforcement,
  ** positive to enable FK enforcement or negative to leave FK enforcement
  ** unchanged.  The second parameter is a pointer to an integer into which
  ** is written 0 or 1 to indicate whether FK enforcement is off or on
  ** following this call.  The second parameter may be a NULL pointer, in
  ** which case the FK enforcement setting is not reported back. </dd>
  **
  ** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]]
  ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
  ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
  ** There should be two additional arguments.
  ** The first argument is an integer which is 0 to disable triggers,
  ** positive to enable triggers or negative to leave the setting unchanged.
  ** The second parameter is a pointer to an integer into which
  ** is written 0 or 1 to indicate whether triggers are disabled or enabled
  ** following this call.  The second parameter may be a NULL pointer, in
  ** which case the trigger setting is not reported back. </dd>
  **
  ** [[SQLITE_DBCONFIG_ENABLE_VIEW]]
  ** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
  ** <dd> ^This option is used to enable or disable [CREATE VIEW | views].
  ** There should be two additional arguments.
  ** The first argument is an integer which is 0 to disable views,
  ** positive to enable views or negative to leave the setting unchanged.
  ** The second parameter is a pointer to an integer into which
  ** is written 0 or 1 to indicate whether views are disabled or enabled
  ** following this call.  The second parameter may be a NULL pointer, in
  ** which case the view setting is not reported back. </dd>
  **
  ** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
  ** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
  ** <dd> ^This option is used to enable or disable the
  ** [fts3_tokenizer()] function which is part of the
  ** [FTS3] full-text search engine extension.
  ** There should be two additional arguments.
  ** The first argument is an integer which is 0 to disable fts3_tokenizer() or
  ** positive to enable fts3_tokenizer() or negative to leave the setting
  ** unchanged.
  ** The second parameter is a pointer to an integer into which
  ** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
  ** following this call.  The second parameter may be a NULL pointer, in
  ** which case the new setting is not reported back. </dd>
  **
  ** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
  ** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
  ** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
  ** interface independently of the [load_extension()] SQL function.
  ** The [sqlite3_enable_load_extension()] API enables or disables both the
  ** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
  ** There should be two additional arguments.
  ** When the first argument to this interface is 1, then only the C-API is
  ** enabled and the SQL function remains disabled.  If the first argument to
  ** this interface is 0, then both the C-API and the SQL function are disabled.
  ** If the first argument is -1, then no changes are made to state of either the
  ** C-API or the SQL function.
  ** The second parameter is a pointer to an integer into which
  ** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
  ** is disabled or enabled following this call.  The second parameter may
  ** be a NULL pointer, in which case the new setting is not reported back.
  ** </dd>
  **
  ** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
  ** <dd> ^This option is used to change the name of the "main" database
  ** schema.  ^The sole argument is a pointer to a constant UTF8 string
  ** which will become the new schema name in place of "main".  ^SQLite
  ** does not make a copy of the new main schema name string, so the application
  ** must ensure that the argument passed into this DBCONFIG option is unchanged
  ** until after the database connection closes.
  ** </dd>
  **
  ** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
  ** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
  ** <dd> Usually, when a database in wal mode is closed or detached from a
  ** database handle, SQLite checks if this will mean that there are now no
  ** connections at all to the database. If so, it performs a checkpoint
  ** operation before closing the connection. This option may be used to
  ** override this behaviour. The first parameter passed to this operation
  ** is an integer - positive to disable checkpoints-on-close, or zero (the
  ** default) to enable them, and negative to leave the setting unchanged.
  ** The second parameter is a pointer to an integer
  ** into which is written 0 or 1 to indicate whether checkpoints-on-close
  ** have been disabled - 0 if they are not disabled, 1 if they are.
  ** </dd>
  **
  ** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
  ** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
  ** the [query planner stability guarantee] (QPSG).  When the QPSG is active,
  ** a single SQL query statement will always use the same algorithm regardless
  ** of values of [bound parameters].)^ The QPSG disables some query optimizations
  ** that look at the values of bound parameters, which can make some queries
  ** slower.  But the QPSG has the advantage of more predictable behavior.  With
  ** the QPSG active, SQLite will always use the same query plan in the field as
  ** was used during testing in the lab.
  ** The first argument to this setting is an integer which is 0 to disable
  ** the QPSG, positive to enable QPSG, or negative to leave the setting
  ** unchanged. The second parameter is a pointer to an integer into which
  ** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
  ** following this call.
  ** </dd>
  **
  ** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
  ** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
  ** include output for any operations performed by trigger programs. This
  ** option is used to set or clear (the default) a flag that governs this
  ** behavior. The first parameter passed to this operation is an integer -
  ** positive to enable output for trigger programs, or zero to disable it,
  ** or negative to leave the setting unchanged.
  ** The second parameter is a pointer to an integer into which is written
  ** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
  ** it is not disabled, 1 if it is.
  ** </dd>
  **
  ** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
  ** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
  ** [VACUUM] in order to reset a database back to an empty database
  ** with no schema and no content. The following process works even for
  ** a badly corrupted database file:
  ** <ol>
  ** <li> If the database connection is newly opened, make sure it has read the
  **      database schema by preparing then discarding some query against the
  **      database, or calling sqlite3_table_column_metadata(), ignoring any
  **      errors.  This step is only necessary if the application desires to keep
  **      the database in WAL mode after the reset if it was in WAL mode before
  **      the reset.
  ** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
  ** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
  ** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
  ** </ol>
  ** Because resetting a database is destructive and irreversible, the
  ** process requires the use of this obscure API and multiple steps to help
  ** ensure that it does not happen by accident.
  **
  ** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
  ** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
  ** "defensive" flag for a database connection.  When the defensive
  ** flag is enabled, language features that allow ordinary SQL to
  ** deliberately corrupt the database file are disabled.  The disabled
  ** features include but are not limited to the following:
  ** <ul>
  ** <li> The [PRAGMA writable_schema=ON] statement.
  ** <li> The [PRAGMA journal_mode=OFF] statement.
  ** <li> Writes to the [sqlite_dbpage] virtual table.
  ** <li> Direct writes to [shadow tables].
  ** </ul>
  ** </dd>
  **
  ** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
  ** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
  ** "writable_schema" flag. This has the same effect and is logically equivalent
  ** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
  ** The first argument to this setting is an integer which is 0 to disable
  ** the writable_schema, positive to enable writable_schema, or negative to
  ** leave the setting unchanged. The second parameter is a pointer to an
  ** integer into which is written 0 or 1 to indicate whether the writable_schema
  ** is enabled or disabled following this call.
  ** </dd>
  **
  ** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]]
  ** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
  ** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
  ** the legacy behavior of the [ALTER TABLE RENAME] command such it
  ** behaves as it did prior to [version 3.24.0] (2018-06-04).  See the
  ** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for
  ** additional information. This feature can also be turned on and off
  ** using the [PRAGMA legacy_alter_table] statement.
  ** </dd>
  **
  ** [[SQLITE_DBCONFIG_DQS_DML]]
  ** <dt>SQLITE_DBCONFIG_DQS_DML</td>
  ** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
  ** the legacy [double-quoted string literal] misfeature for DML statements
  ** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
  ** default value of this setting is determined by the [-DSQLITE_DQS]
  ** compile-time option.
  ** </dd>
  **
  ** [[SQLITE_DBCONFIG_DQS_DDL]]
  ** <dt>SQLITE_DBCONFIG_DQS_DDL</td>
  ** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
  ** the legacy [double-quoted string literal] misfeature for DDL statements,
  ** such as CREATE TABLE and CREATE INDEX. The
  ** default value of this setting is determined by the [-DSQLITE_DQS]
  ** compile-time option.
  ** </dd>
  **
  ** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]]
  ** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</td>
  ** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
  ** assume that database schemas are untainted by malicious content.
  ** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
  ** takes additional defensive steps to protect the application from harm
  ** including:
  ** <ul>
  ** <li> Prohibit the use of SQL functions inside triggers, views,
  ** CHECK constraints, DEFAULT clauses, expression indexes,
  ** partial indexes, or generated columns
  ** unless those functions are tagged with [SQLITE_INNOCUOUS].
  ** <li> Prohibit the use of virtual tables inside of triggers or views
  ** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS].
  ** </ul>
  ** This setting defaults to "on" for legacy compatibility, however
  ** all applications are advised to turn it off if possible. This setting
  ** can also be controlled using the [PRAGMA trusted_schema] statement.
  ** </dd>
  **
  ** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]]
  ** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</td>
  ** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
  ** the legacy file format flag.  When activated, this flag causes all newly
  ** created database file to have a schema format version number (the 4-byte
  ** integer found at offset 44 into the database header) of 1.  This in turn
  ** means that the resulting database file will be readable and writable by
  ** any SQLite version back to 3.0.0 ([dateof:3.0.0]).  Without this setting,
  ** newly created databases are generally not understandable by SQLite versions
  ** prior to 3.3.0 ([dateof:3.3.0]).  As these words are written, there
  ** is now scarcely any need to generated database files that are compatible
  ** all the way back to version 3.0.0, and so this setting is of little
  ** practical use, but is provided so that SQLite can continue to claim the
  ** ability to generate new database files that are compatible with  version
  ** 3.0.0.
  ** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
  ** the [VACUUM] command will fail with an obscure error when attempting to
  ** process a table with generated columns and a descending index.  This is
  ** not considered a bug since SQLite versions 3.3.0 and earlier do not support
  ** either generated columns or decending indexes.
  ** </dd>
  ** </dl>
  */
  #define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
  #define SQLITE_DBCONFIG_LOOKASIDE             1001 /* void* int int */
  #define SQLITE_DBCONFIG_ENABLE_FKEY           1002 /* int int* */
  #define SQLITE_DBCONFIG_ENABLE_TRIGGER        1003 /* int int* */
  #define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
  #define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
  #define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
  #define SQLITE_DBCONFIG_ENABLE_QPSG           1007 /* int int* */
  #define SQLITE_DBCONFIG_TRIGGER_EQP           1008 /* int int* */
  #define SQLITE_DBCONFIG_RESET_DATABASE        1009 /* int int* */
  #define SQLITE_DBCONFIG_DEFENSIVE             1010 /* int int* */
  #define SQLITE_DBCONFIG_WRITABLE_SCHEMA       1011 /* int int* */
  #define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE    1012 /* int int* */
  #define SQLITE_DBCONFIG_DQS_DML               1013 /* int int* */
  #define SQLITE_DBCONFIG_DQS_DDL               1014 /* int int* */
  #define SQLITE_DBCONFIG_ENABLE_VIEW           1015 /* int int* */
  #define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT    1016 /* int int* */
  #define SQLITE_DBCONFIG_TRUSTED_SCHEMA        1017 /* int int* */
  #define SQLITE_DBCONFIG_MAX                   1017 /* Largest DBCONFIG */
  
  /*
  ** CAPI3REF: Enable Or Disable Extended Result Codes
  ** METHOD: sqlite3
  **
  ** ^The sqlite3_extended_result_codes() routine enables or disables the
  ** [extended result codes] feature of SQLite. ^The extended result
  ** codes are disabled by default for historical compatibility.
  */
  SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
  
  /*
  ** CAPI3REF: Last Insert Rowid
  ** METHOD: sqlite3
  **
  ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
  ** has a unique 64-bit signed
  ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
  ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
  ** names are not also used by explicitly declared columns. ^If
  ** the table has a column of type [INTEGER PRIMARY KEY] then that column
  ** is another alias for the rowid.
  **
  ** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
  ** the most recent successful [INSERT] into a rowid table or [virtual table]
  ** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
  ** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
  ** on the database connection D, then sqlite3_last_insert_rowid(D) returns
  ** zero.
  **
  ** As well as being set automatically as rows are inserted into database
  ** tables, the value returned by this function may be set explicitly by
  ** [sqlite3_set_last_insert_rowid()]
  **
  ** Some virtual table implementations may INSERT rows into rowid tables as
  ** part of committing a transaction (e.g. to flush data accumulated in memory
  ** to disk). In this case subsequent calls to this function return the rowid
  ** associated with these internal INSERT operations, which leads to
  ** unintuitive results. Virtual table implementations that do write to rowid
  ** tables in this way can avoid this problem by restoring the original
  ** rowid value using [sqlite3_set_last_insert_rowid()] before returning
  ** control to the user.
  **
  ** ^(If an [INSERT] occurs within a trigger then this routine will
  ** return the [rowid] of the inserted row as long as the trigger is
  ** running. Once the trigger program ends, the value returned
  ** by this routine reverts to what it was before the trigger was fired.)^
  **
  ** ^An [INSERT] that fails due to a constraint violation is not a
  ** successful [INSERT] and does not change the value returned by this
  ** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
  ** and INSERT OR ABORT make no changes to the return value of this
  ** routine when their insertion fails.  ^(When INSERT OR REPLACE
  ** encounters a constraint violation, it does not fail.  The
  ** INSERT continues to completion after deleting rows that caused
  ** the constraint problem so INSERT OR REPLACE will always change
  ** the return value of this interface.)^
  **
  ** ^For the purposes of this routine, an [INSERT] is considered to
  ** be successful even if it is subsequently rolled back.
  **
  ** This function is accessible to SQL statements via the
  ** [last_insert_rowid() SQL function].
  **
  ** If a separate thread performs a new [INSERT] on the same
  ** database connection while the [sqlite3_last_insert_rowid()]
  ** function is running and thus changes the last insert [rowid],
  ** then the value returned by [sqlite3_last_insert_rowid()] is
  ** unpredictable and might not equal either the old or the new
  ** last insert [rowid].
  */
  SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
  
  /*
  ** CAPI3REF: Set the Last Insert Rowid value.
  ** METHOD: sqlite3
  **
  ** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
  ** set the value returned by calling sqlite3_last_insert_rowid(D) to R
  ** without inserting a row into the database.
  */
  SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
  
  /*
  ** CAPI3REF: Count The Number Of Rows Modified
  ** METHOD: sqlite3
  **
  ** ^This function returns the number of rows modified, inserted or
  ** deleted by the most recently completed INSERT, UPDATE or DELETE
  ** statement on the database connection specified by the only parameter.
  ** ^Executing any other type of SQL statement does not modify the value
  ** returned by this function.
  **
  ** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
  ** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
  ** [foreign key actions] or [REPLACE] constraint resolution are not counted.
  **
  ** Changes to a view that are intercepted by
  ** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
  ** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
  ** DELETE statement run on a view is always zero. Only changes made to real
  ** tables are counted.
  **
  ** Things are more complicated if the sqlite3_changes() function is
  ** executed while a trigger program is running. This may happen if the
  ** program uses the [changes() SQL function], or if some other callback
  ** function invokes sqlite3_changes() directly. Essentially:
  **
  ** <ul>
  **   <li> ^(Before entering a trigger program the value returned by
  **        sqlite3_changes() function is saved. After the trigger program
  **        has finished, the original value is restored.)^
  **
  **   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
  **        statement sets the value returned by sqlite3_changes()
  **        upon completion as normal. Of course, this value will not include
  **        any changes performed by sub-triggers, as the sqlite3_changes()
  **        value will be saved and restored after each sub-trigger has run.)^
  ** </ul>
  **
  ** ^This means that if the changes() SQL function (or similar) is used
  ** by the first INSERT, UPDATE or DELETE statement within a trigger, it
  ** returns the value as set when the calling statement began executing.
  ** ^If it is used by the second or subsequent such statement within a trigger
  ** program, the value returned reflects the number of rows modified by the
  ** previous INSERT, UPDATE or DELETE statement within the same trigger.
  **
  ** If a separate thread makes changes on the same database connection
  ** while [sqlite3_changes()] is running then the value returned
  ** is unpredictable and not meaningful.
  **
  ** See also:
  ** <ul>
  ** <li> the [sqlite3_total_changes()] interface
  ** <li> the [count_changes pragma]
  ** <li> the [changes() SQL function]
  ** <li> the [data_version pragma]
  ** </ul>
  */
  SQLITE_API int sqlite3_changes(sqlite3*);
  
  /*
  ** CAPI3REF: Total Number Of Rows Modified
  ** METHOD: sqlite3
  **
  ** ^This function returns the total number of rows inserted, modified or
  ** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
  ** since the database connection was opened, including those executed as
  ** part of trigger programs. ^Executing any other type of SQL statement
  ** does not affect the value returned by sqlite3_total_changes().
  **
  ** ^Changes made as part of [foreign key actions] are included in the
  ** count, but those made as part of REPLACE constraint resolution are
  ** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
  ** are not counted.
  **
  ** The [sqlite3_total_changes(D)] interface only reports the number
  ** of rows that changed due to SQL statement run against database
  ** connection D.  Any changes by other database connections are ignored.
  ** To detect changes against a database file from other database
  ** connections use the [PRAGMA data_version] command or the
  ** [SQLITE_FCNTL_DATA_VERSION] [file control].
  **
  ** If a separate thread makes changes on the same database connection
  ** while [sqlite3_total_changes()] is running then the value
  ** returned is unpredictable and not meaningful.
  **
  ** See also:
  ** <ul>
  ** <li> the [sqlite3_changes()] interface
  ** <li> the [count_changes pragma]
  ** <li> the [changes() SQL function]
  ** <li> the [data_version pragma]
  ** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
  ** </ul>
  */
  SQLITE_API int sqlite3_total_changes(sqlite3*);
  
  /*
  ** CAPI3REF: Interrupt A Long-Running Query
  ** METHOD: sqlite3
  **
  ** ^This function causes any pending database operation to abort and
  ** return at its earliest opportunity. This routine is typically
  ** called in response to a user action such as pressing "Cancel"
  ** or Ctrl-C where the user wants a long query operation to halt
  ** immediately.
  **
  ** ^It is safe to call this routine from a thread different from the
  ** thread that is currently running the database operation.  But it
  ** is not safe to call this routine with a [database connection] that
  ** is closed or might close before sqlite3_interrupt() returns.
  **
  ** ^If an SQL operation is very nearly finished at the time when
  ** sqlite3_interrupt() is called, then it might not have an opportunity
  ** to be interrupted and might continue to completion.
  **
  ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
  ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
  ** that is inside an explicit transaction, then the entire transaction
  ** will be rolled back automatically.
  **
  ** ^The sqlite3_interrupt(D) call is in effect until all currently running
  ** SQL statements on [database connection] D complete.  ^Any new SQL statements
  ** that are started after the sqlite3_interrupt() call and before the
  ** running statement count reaches zero are interrupted as if they had been
  ** running prior to the sqlite3_interrupt() call.  ^New SQL statements
  ** that are started after the running statement count reaches zero are
  ** not effected by the sqlite3_interrupt().
  ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
  ** SQL statements is a no-op and has no effect on SQL statements
  ** that are started after the sqlite3_interrupt() call returns.
  */
  SQLITE_API void sqlite3_interrupt(sqlite3*);
  
  /*
  ** CAPI3REF: Determine If An SQL Statement Is Complete
  **
  ** These routines are useful during command-line input to determine if the
  ** currently entered text seems to form a complete SQL statement or
  ** if additional input is needed before sending the text into
  ** SQLite for parsing.  ^These routines return 1 if the input string
  ** appears to be a complete SQL statement.  ^A statement is judged to be
  ** complete if it ends with a semicolon token and is not a prefix of a
  ** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
  ** string literals or quoted identifier names or comments are not
  ** independent tokens (they are part of the token in which they are
  ** embedded) and thus do not count as a statement terminator.  ^Whitespace
  ** and comments that follow the final semicolon are ignored.
  **
  ** ^These routines return 0 if the statement is incomplete.  ^If a
  ** memory allocation fails, then SQLITE_NOMEM is returned.
  **
  ** ^These routines do not parse the SQL statements thus
  ** will not detect syntactically incorrect SQL.
  **
  ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
  ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
  ** automatically by sqlite3_complete16().  If that initialization fails,
  ** then the return value from sqlite3_complete16() will be non-zero
  ** regardless of whether or not the input SQL is complete.)^
  **
  ** The input to [sqlite3_complete()] must be a zero-terminated
  ** UTF-8 string.
  **
  ** The input to [sqlite3_complete16()] must be a zero-terminated
  ** UTF-16 string in native byte order.
  */
  SQLITE_API int sqlite3_complete(const char *sql);
  SQLITE_API int sqlite3_complete16(const void *sql);
  
  /*
  ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
  ** KEYWORDS: {busy-handler callback} {busy handler}
  ** METHOD: sqlite3
  **
  ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
  ** that might be invoked with argument P whenever
  ** an attempt is made to access a database table associated with
  ** [database connection] D when another thread
  ** or process has the table locked.
  ** The sqlite3_busy_handler() interface is used to implement
  ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
  **
  ** ^If the busy callback is NULL, then [SQLITE_BUSY]
  ** is returned immediately upon encountering the lock.  ^If the busy callback
  ** is not NULL, then the callback might be invoked with two arguments.
  **
  ** ^The first argument to the busy handler is a copy of the void* pointer which
  ** is the third argument to sqlite3_busy_handler().  ^The second argument to
  ** the busy handler callback is the number of times that the busy handler has
  ** been invoked previously for the same locking event.  ^If the
  ** busy callback returns 0, then no additional attempts are made to
  ** access the database and [SQLITE_BUSY] is returned
  ** to the application.
  ** ^If the callback returns non-zero, then another attempt
  ** is made to access the database and the cycle repeats.
  **
  ** The presence of a busy handler does not guarantee that it will be invoked
  ** when there is lock contention. ^If SQLite determines that invoking the busy
  ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
  ** to the application instead of invoking the
  ** busy handler.
  ** Consider a scenario where one process is holding a read lock that
  ** it is trying to promote to a reserved lock and
  ** a second process is holding a reserved lock that it is trying
  ** to promote to an exclusive lock.  The first process cannot proceed
  ** because it is blocked by the second and the second process cannot
  ** proceed because it is blocked by the first.  If both processes
  ** invoke the busy handlers, neither will make any progress.  Therefore,
  ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
  ** will induce the first process to release its read lock and allow
  ** the second process to proceed.
  **
  ** ^The default busy callback is NULL.
  **
  ** ^(There can only be a single busy handler defined for each
  ** [database connection].  Setting a new busy handler clears any
  ** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
  ** or evaluating [PRAGMA busy_timeout=N] will change the
  ** busy handler and thus clear any previously set busy handler.
  **
  ** The busy callback should not take any actions which modify the
  ** database connection that invoked the busy handler.  In other words,
  ** the busy handler is not reentrant.  Any such actions
  ** result in undefined behavior.
  **
  ** A busy handler must not close the database connection
  ** or [prepared statement] that invoked the busy handler.
  */
  SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
  
  /*
  ** CAPI3REF: Set A Busy Timeout
  ** METHOD: sqlite3
  **
  ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
  ** for a specified amount of time when a table is locked.  ^The handler
  ** will sleep multiple times until at least "ms" milliseconds of sleeping
  ** have accumulated.  ^After at least "ms" milliseconds of sleeping,
  ** the handler returns 0 which causes [sqlite3_step()] to return
  ** [SQLITE_BUSY].
  **
  ** ^Calling this routine with an argument less than or equal to zero
  ** turns off all busy handlers.
  **
  ** ^(There can only be a single busy handler for a particular
  ** [database connection] at any given moment.  If another busy handler
  ** was defined  (using [sqlite3_busy_handler()]) prior to calling
  ** this routine, that other busy handler is cleared.)^
  **
  ** See also:  [PRAGMA busy_timeout]
  */
  SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
  
  /*
  ** CAPI3REF: Convenience Routines For Running Queries
  ** METHOD: sqlite3
  **
  ** This is a legacy interface that is preserved for backwards compatibility.
  ** Use of this interface is not recommended.
  **
  ** Definition: A <b>result table</b> is memory data structure created by the
  ** [sqlite3_get_table()] interface.  A result table records the
  ** complete query results from one or more queries.
  **
  ** The table conceptually has a number of rows and columns.  But
  ** these numbers are not part of the result table itself.  These
  ** numbers are obtained separately.  Let N be the number of rows
  ** and M be the number of columns.
  **
  ** A result table is an array of pointers to zero-terminated UTF-8 strings.
  ** There are (N+1)*M elements in the array.  The first M pointers point
  ** to zero-terminated strings that  contain the names of the columns.
  ** The remaining entries all point to query results.  NULL values result
  ** in NULL pointers.  All other values are in their UTF-8 zero-terminated
  ** string representation as returned by [sqlite3_column_text()].
  **
  ** A result table might consist of one or more memory allocations.
  ** It is not safe to pass a result table directly to [sqlite3_free()].
  ** A result table should be deallocated using [sqlite3_free_table()].
  **
  ** ^(As an example of the result table format, suppose a query result
  ** is as follows:
  **
  ** <blockquote><pre>
  **        Name        | Age
  **        -----------------------
  **        Alice       | 43
  **        Bob         | 28
  **        Cindy       | 21
  ** </pre></blockquote>
  **
  ** There are two columns (M==2) and three rows (N==3).  Thus the
  ** result table has 8 entries.  Suppose the result table is stored
  ** in an array named azResult.  Then azResult holds this content:
  **
  ** <blockquote><pre>
  **        azResult&#91;0] = "Name";
  **        azResult&#91;1] = "Age";
  **        azResult&#91;2] = "Alice";
  **        azResult&#91;3] = "43";
  **        azResult&#91;4] = "Bob";
  **        azResult&#91;5] = "28";
  **        azResult&#91;6] = "Cindy";
  **        azResult&#91;7] = "21";
  ** </pre></blockquote>)^
  **
  ** ^The sqlite3_get_table() function evaluates one or more
  ** semicolon-separated SQL statements in the zero-terminated UTF-8
  ** string of its 2nd parameter and returns a result table to the
  ** pointer given in its 3rd parameter.
  **
  ** After the application has finished with the result from sqlite3_get_table(),
  ** it must pass the result table pointer to sqlite3_free_table() in order to
  ** release the memory that was malloced.  Because of the way the
  ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
  ** function must not try to call [sqlite3_free()] directly.  Only
  ** [sqlite3_free_table()] is able to release the memory properly and safely.
  **
  ** The sqlite3_get_table() interface is implemented as a wrapper around
  ** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
  ** to any internal data structures of SQLite.  It uses only the public
  ** interface defined here.  As a consequence, errors that occur in the
  ** wrapper layer outside of the internal [sqlite3_exec()] call are not
  ** reflected in subsequent calls to [sqlite3_errcode()] or
  ** [sqlite3_errmsg()].
  */
  SQLITE_API int sqlite3_get_table(
    sqlite3 *db,          /* An open database */
    const char *zSql,     /* SQL to be evaluated */
    char ***pazResult,    /* Results of the query */
    int *pnRow,           /* Number of result rows written here */
    int *pnColumn,        /* Number of result columns written here */
    char **pzErrmsg       /* Error msg written here */
  );
  SQLITE_API void sqlite3_free_table(char **result);
  
  /*
  ** CAPI3REF: Formatted String Printing Functions
  **
  ** These routines are work-alikes of the "printf()" family of functions
  ** from the standard C library.
  ** These routines understand most of the common formatting options from
  ** the standard library printf()
  ** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
  ** See the [built-in printf()] documentation for details.
  **
  ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
  ** results into memory obtained from [sqlite3_malloc64()].
  ** The strings returned by these two routines should be
  ** released by [sqlite3_free()].  ^Both routines return a
  ** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
  ** memory to hold the resulting string.
  **
  ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
  ** the standard C library.  The result is written into the
  ** buffer supplied as the second parameter whose size is given by
  ** the first parameter. Note that the order of the
  ** first two parameters is reversed from snprintf().)^  This is an
  ** historical accident that cannot be fixed without breaking
  ** backwards compatibility.  ^(Note also that sqlite3_snprintf()
  ** returns a pointer to its buffer instead of the number of
  ** characters actually written into the buffer.)^  We admit that
  ** the number of characters written would be a more useful return
  ** value but we cannot change the implementation of sqlite3_snprintf()
  ** now without breaking compatibility.
  **
  ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
  ** guarantees that the buffer is always zero-terminated.  ^The first
  ** parameter "n" is the total size of the buffer, including space for
  ** the zero terminator.  So the longest string that can be completely
  ** written will be n-1 characters.
  **
  ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
  **
  ** See also:  [built-in printf()], [printf() SQL function]
  */
  SQLITE_API char *sqlite3_mprintf(const char*,...);
  SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
  SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
  SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
  
  /*
  ** CAPI3REF: Memory Allocation Subsystem
  **
  ** The SQLite core uses these three routines for all of its own
  ** internal memory allocation needs. "Core" in the previous sentence
  ** does not include operating-system specific [VFS] implementation.  The
  ** Windows VFS uses native malloc() and free() for some operations.
  **
  ** ^The sqlite3_malloc() routine returns a pointer to a block
  ** of memory at least N bytes in length, where N is the parameter.
  ** ^If sqlite3_malloc() is unable to obtain sufficient free
  ** memory, it returns a NULL pointer.  ^If the parameter N to
  ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
  ** a NULL pointer.
  **
  ** ^The sqlite3_malloc64(N) routine works just like
  ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
  ** of a signed 32-bit integer.
  **
  ** ^Calling sqlite3_free() with a pointer previously returned
  ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
  ** that it might be reused.  ^The sqlite3_free() routine is
  ** a no-op if is called with a NULL pointer.  Passing a NULL pointer
  ** to sqlite3_free() is harmless.  After being freed, memory
  ** should neither be read nor written.  Even reading previously freed
  ** memory might result in a segmentation fault or other severe error.
  ** Memory corruption, a segmentation fault, or other severe error
  ** might result if sqlite3_free() is called with a non-NULL pointer that
  ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
  **
  ** ^The sqlite3_realloc(X,N) interface attempts to resize a
  ** prior memory allocation X to be at least N bytes.
  ** ^If the X parameter to sqlite3_realloc(X,N)
  ** is a NULL pointer then its behavior is identical to calling
  ** sqlite3_malloc(N).
  ** ^If the N parameter to sqlite3_realloc(X,N) is zero or
  ** negative then the behavior is exactly the same as calling
  ** sqlite3_free(X).
  ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
  ** of at least N bytes in size or NULL if insufficient memory is available.
  ** ^If M is the size of the prior allocation, then min(N,M) bytes
  ** of the prior allocation are copied into the beginning of buffer returned
  ** by sqlite3_realloc(X,N) and the prior allocation is freed.
  ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
  ** prior allocation is not freed.
  **
  ** ^The sqlite3_realloc64(X,N) interfaces works the same as
  ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
  ** of a 32-bit signed integer.
  **
  ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
  ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
  ** sqlite3_msize(X) returns the size of that memory allocation in bytes.
  ** ^The value returned by sqlite3_msize(X) might be larger than the number
  ** of bytes requested when X was allocated.  ^If X is a NULL pointer then
  ** sqlite3_msize(X) returns zero.  If X points to something that is not
  ** the beginning of memory allocation, or if it points to a formerly
  ** valid memory allocation that has now been freed, then the behavior
  ** of sqlite3_msize(X) is undefined and possibly harmful.
  **
  ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
  ** sqlite3_malloc64(), and sqlite3_realloc64()
  ** is always aligned to at least an 8 byte boundary, or to a
  ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
  ** option is used.
  **
  ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
  ** must be either NULL or else pointers obtained from a prior
  ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
  ** not yet been released.
  **
  ** The application must not read or write any part of
  ** a block of memory after it has been released using
  ** [sqlite3_free()] or [sqlite3_realloc()].
  */
  SQLITE_API void *sqlite3_malloc(int);
  SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
  SQLITE_API void *sqlite3_realloc(void*, int);
  SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
  SQLITE_API void sqlite3_free(void*);
  SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
  
  /*
  ** CAPI3REF: Memory Allocator Statistics
  **
  ** SQLite provides these two interfaces for reporting on the status
  ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
  ** routines, which form the built-in memory allocation subsystem.
  **
  ** ^The [sqlite3_memory_used()] routine returns the number of bytes
  ** of memory currently outstanding (malloced but not freed).
  ** ^The [sqlite3_memory_highwater()] routine returns the maximum
  ** value of [sqlite3_memory_used()] since the high-water mark
  ** was last reset.  ^The values returned by [sqlite3_memory_used()] and
  ** [sqlite3_memory_highwater()] include any overhead
  ** added by SQLite in its implementation of [sqlite3_malloc()],
  ** but not overhead added by the any underlying system library
  ** routines that [sqlite3_malloc()] may call.
  **
  ** ^The memory high-water mark is reset to the current value of
  ** [sqlite3_memory_used()] if and only if the parameter to
  ** [sqlite3_memory_highwater()] is true.  ^The value returned
  ** by [sqlite3_memory_highwater(1)] is the high-water mark
  ** prior to the reset.
  */
  SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
  SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
  
  /*
  ** CAPI3REF: Pseudo-Random Number Generator
  **
  ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
  ** select random [ROWID | ROWIDs] when inserting new records into a table that
  ** already uses the largest possible [ROWID].  The PRNG is also used for
  ** the built-in random() and randomblob() SQL functions.  This interface allows
  ** applications to access the same PRNG for other purposes.
  **
  ** ^A call to this routine stores N bytes of randomness into buffer P.
  ** ^The P parameter can be a NULL pointer.
  **
  ** ^If this routine has not been previously called or if the previous
  ** call had N less than one or a NULL pointer for P, then the PRNG is
  ** seeded using randomness obtained from the xRandomness method of
  ** the default [sqlite3_vfs] object.
  ** ^If the previous call to this routine had an N of 1 or more and a
  ** non-NULL P then the pseudo-randomness is generated
  ** internally and without recourse to the [sqlite3_vfs] xRandomness
  ** method.
  */
  SQLITE_API void sqlite3_randomness(int N, void *P);
  
  /*
  ** CAPI3REF: Compile-Time Authorization Callbacks
  ** METHOD: sqlite3
  ** KEYWORDS: {authorizer callback}
  **
  ** ^This routine registers an authorizer callback with a particular
  ** [database connection], supplied in the first argument.
  ** ^The authorizer callback is invoked as SQL statements are being compiled
  ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
  ** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
  ** and [sqlite3_prepare16_v3()].  ^At various
  ** points during the compilation process, as logic is being created
  ** to perform various actions, the authorizer callback is invoked to
  ** see if those actions are allowed.  ^The authorizer callback should
  ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
  ** specific action but allow the SQL statement to continue to be
  ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
  ** rejected with an error.  ^If the authorizer callback returns
  ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
  ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
  ** the authorizer will fail with an error message.
  **
  ** When the callback returns [SQLITE_OK], that means the operation
  ** requested is ok.  ^When the callback returns [SQLITE_DENY], the
  ** [sqlite3_prepare_v2()] or equivalent call that triggered the
  ** authorizer will fail with an error message explaining that
  ** access is denied.
  **
  ** ^The first parameter to the authorizer callback is a copy of the third
  ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
  ** to the callback is an integer [SQLITE_COPY | action code] that specifies
  ** the particular action to be authorized. ^The third through sixth parameters
  ** to the callback are either NULL pointers or zero-terminated strings
  ** that contain additional details about the action to be authorized.
  ** Applications must always be prepared to encounter a NULL pointer in any
  ** of the third through the sixth parameters of the authorization callback.
  **
  ** ^If the action code is [SQLITE_READ]
  ** and the callback returns [SQLITE_IGNORE] then the
  ** [prepared statement] statement is constructed to substitute
  ** a NULL value in place of the table column that would have
  ** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
  ** return can be used to deny an untrusted user access to individual
  ** columns of a table.
  ** ^When a table is referenced by a [SELECT] but no column values are
  ** extracted from that table (for example in a query like
  ** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
  ** is invoked once for that table with a column name that is an empty string.
  ** ^If the action code is [SQLITE_DELETE] and the callback returns
  ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
  ** [truncate optimization] is disabled and all rows are deleted individually.
  **
  ** An authorizer is used when [sqlite3_prepare | preparing]
  ** SQL statements from an untrusted source, to ensure that the SQL statements
  ** do not try to access data they are not allowed to see, or that they do not
  ** try to execute malicious statements that damage the database.  For
  ** example, an application may allow a user to enter arbitrary
  ** SQL queries for evaluation by a database.  But the application does
  ** not want the user to be able to make arbitrary changes to the
  ** database.  An authorizer could then be put in place while the
  ** user-entered SQL is being [sqlite3_prepare | prepared] that
  ** disallows everything except [SELECT] statements.
  **
  ** Applications that need to process SQL from untrusted sources
  ** might also consider lowering resource limits using [sqlite3_limit()]
  ** and limiting database size using the [max_page_count] [PRAGMA]
  ** in addition to using an authorizer.
  **
  ** ^(Only a single authorizer can be in place on a database connection
  ** at a time.  Each call to sqlite3_set_authorizer overrides the
  ** previous call.)^  ^Disable the authorizer by installing a NULL callback.
  ** The authorizer is disabled by default.
  **
  ** The authorizer callback must not do anything that will modify
  ** the database connection that invoked the authorizer callback.
  ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
  ** database connections for the meaning of "modify" in this paragraph.
  **
  ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
  ** statement might be re-prepared during [sqlite3_step()] due to a
  ** schema change.  Hence, the application should ensure that the
  ** correct authorizer callback remains in place during the [sqlite3_step()].
  **
  ** ^Note that the authorizer callback is invoked only during
  ** [sqlite3_prepare()] or its variants.  Authorization is not
  ** performed during statement evaluation in [sqlite3_step()], unless
  ** as stated in the previous paragraph, sqlite3_step() invokes
  ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
  */
  SQLITE_API int sqlite3_set_authorizer(
    sqlite3*,
    int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
    void *pUserData
  );
  
  /*
  ** CAPI3REF: Authorizer Return Codes
  **
  ** The [sqlite3_set_authorizer | authorizer callback function] must
  ** return either [SQLITE_OK] or one of these two constants in order
  ** to signal SQLite whether or not the action is permitted.  See the
  ** [sqlite3_set_authorizer | authorizer documentation] for additional
  ** information.
  **
  ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
  ** returned from the [sqlite3_vtab_on_conflict()] interface.
  */
  #define SQLITE_DENY   1   /* Abort the SQL statement with an error */
  #define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
  
  /*
  ** CAPI3REF: Authorizer Action Codes
  **
  ** The [sqlite3_set_authorizer()] interface registers a callback function
  ** that is invoked to authorize certain SQL statement actions.  The
  ** second parameter to the callback is an integer code that specifies
  ** what action is being authorized.  These are the integer action codes that
  ** the authorizer callback may be passed.
  **
  ** These action code values signify what kind of operation is to be
  ** authorized.  The 3rd and 4th parameters to the authorization
  ** callback function will be parameters or NULL depending on which of these
  ** codes is used as the second parameter.  ^(The 5th parameter to the
  ** authorizer callback is the name of the database ("main", "temp",
  ** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
  ** is the name of the inner-most trigger or view that is responsible for
  ** the access attempt or NULL if this access attempt is directly from
  ** top-level SQL code.
  */
  /******************************************* 3rd ************ 4th ***********/
  #define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
  #define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
  #define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
  #define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
  #define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
  #define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
  #define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
  #define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
  #define SQLITE_DELETE                9   /* Table Name      NULL            */
  #define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
  #define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
  #define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
  #define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
  #define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
  #define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
  #define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
  #define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
  #define SQLITE_INSERT               18   /* Table Name      NULL            */
  #define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
  #define SQLITE_READ                 20   /* Table Name      Column Name     */
  #define SQLITE_SELECT               21   /* NULL            NULL            */
  #define SQLITE_TRANSACTION          22   /* Operation       NULL            */
  #define SQLITE_UPDATE               23   /* Table Name      Column Name     */
  #define SQLITE_ATTACH               24   /* Filename        NULL            */
  #define SQLITE_DETACH               25   /* Database Name   NULL            */
  #define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
  #define SQLITE_REINDEX              27   /* Index Name      NULL            */
  #define SQLITE_ANALYZE              28   /* Table Name      NULL            */
  #define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
  #define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
  #define SQLITE_FUNCTION             31   /* NULL            Function Name   */
  #define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
  #define SQLITE_COPY                  0   /* No longer used */
  #define SQLITE_RECURSIVE            33   /* NULL            NULL            */
  
  /*
  ** CAPI3REF: Tracing And Profiling Functions
  ** METHOD: sqlite3
  **
  ** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
  ** instead of the routines described here.
  **
  ** These routines register callback functions that can be used for
  ** tracing and profiling the execution of SQL statements.
  **
  ** ^The callback function registered by sqlite3_trace() is invoked at
  ** various times when an SQL statement is being run by [sqlite3_step()].
  ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
  ** SQL statement text as the statement first begins executing.
  ** ^(Additional sqlite3_trace() callbacks might occur
  ** as each triggered subprogram is entered.  The callbacks for triggers
  ** contain a UTF-8 SQL comment that identifies the trigger.)^
  **
  ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
  ** the length of [bound parameter] expansion in the output of sqlite3_trace().
  **
  ** ^The callback function registered by sqlite3_profile() is invoked
  ** as each SQL statement finishes.  ^The profile callback contains
  ** the original statement text and an estimate of wall-clock time
  ** of how long that statement took to run.  ^The profile callback
  ** time is in units of nanoseconds, however the current implementation
  ** is only capable of millisecond resolution so the six least significant
  ** digits in the time are meaningless.  Future versions of SQLite
  ** might provide greater resolution on the profiler callback.  Invoking
  ** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
  ** profile callback.
  */
  SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
     void(*xTrace)(void*,const char*), void*);
  SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
     void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
  
  /*
  ** CAPI3REF: SQL Trace Event Codes
  ** KEYWORDS: SQLITE_TRACE
  **
  ** These constants identify classes of events that can be monitored
  ** using the [sqlite3_trace_v2()] tracing logic.  The M argument
  ** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
  ** the following constants.  ^The first argument to the trace callback
  ** is one of the following constants.
  **
  ** New tracing constants may be added in future releases.
  **
  ** ^A trace callback has four arguments: xCallback(T,C,P,X).
  ** ^The T argument is one of the integer type codes above.
  ** ^The C argument is a copy of the context pointer passed in as the
  ** fourth argument to [sqlite3_trace_v2()].
  ** The P and X arguments are pointers whose meanings depend on T.
  **
  ** <dl>
  ** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
  ** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
  ** first begins running and possibly at other times during the
  ** execution of the prepared statement, such as at the start of each
  ** trigger subprogram. ^The P argument is a pointer to the
  ** [prepared statement]. ^The X argument is a pointer to a string which
  ** is the unexpanded SQL text of the prepared statement or an SQL comment
  ** that indicates the invocation of a trigger.  ^The callback can compute
  ** the same text that would have been returned by the legacy [sqlite3_trace()]
  ** interface by using the X argument when X begins with "--" and invoking
  ** [sqlite3_expanded_sql(P)] otherwise.
  **
  ** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
  ** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
  ** information as is provided by the [sqlite3_profile()] callback.
  ** ^The P argument is a pointer to the [prepared statement] and the
  ** X argument points to a 64-bit integer which is the estimated of
  ** the number of nanosecond that the prepared statement took to run.
  ** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
  **
  ** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
  ** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
  ** statement generates a single row of result.
  ** ^The P argument is a pointer to the [prepared statement] and the
  ** X argument is unused.
  **
  ** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
  ** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
  ** connection closes.
  ** ^The P argument is a pointer to the [database connection] object
  ** and the X argument is unused.
  ** </dl>
  */
  #define SQLITE_TRACE_STMT       0x01
  #define SQLITE_TRACE_PROFILE    0x02
  #define SQLITE_TRACE_ROW        0x04
  #define SQLITE_TRACE_CLOSE      0x08
  
  /*
  ** CAPI3REF: SQL Trace Hook
  ** METHOD: sqlite3
  **
  ** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
  ** function X against [database connection] D, using property mask M
  ** and context pointer P.  ^If the X callback is
  ** NULL or if the M mask is zero, then tracing is disabled.  The
  ** M argument should be the bitwise OR-ed combination of
  ** zero or more [SQLITE_TRACE] constants.
  **
  ** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
  ** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
  **
  ** ^The X callback is invoked whenever any of the events identified by
  ** mask M occur.  ^The integer return value from the callback is currently
  ** ignored, though this may change in future releases.  Callback
  ** implementations should return zero to ensure future compatibility.
  **
  ** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
  ** ^The T argument is one of the [SQLITE_TRACE]
  ** constants to indicate why the callback was invoked.
  ** ^The C argument is a copy of the context pointer.
  ** The P and X arguments are pointers whose meanings depend on T.
  **
  ** The sqlite3_trace_v2() interface is intended to replace the legacy
  ** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
  ** are deprecated.
  */
  SQLITE_API int sqlite3_trace_v2(
    sqlite3*,
    unsigned uMask,
    int(*xCallback)(unsigned,void*,void*,void*),
    void *pCtx
  );
  
  /*
  ** CAPI3REF: Query Progress Callbacks
  ** METHOD: sqlite3
  **
  ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
  ** function X to be invoked periodically during long running calls to
  ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
  ** database connection D.  An example use for this
  ** interface is to keep a GUI updated during a large query.
  **
  ** ^The parameter P is passed through as the only parameter to the
  ** callback function X.  ^The parameter N is the approximate number of
  ** [virtual machine instructions] that are evaluated between successive
  ** invocations of the callback X.  ^If N is less than one then the progress
  ** handler is disabled.
  **
  ** ^Only a single progress handler may be defined at one time per
  ** [database connection]; setting a new progress handler cancels the
  ** old one.  ^Setting parameter X to NULL disables the progress handler.
  ** ^The progress handler is also disabled by setting N to a value less
  ** than 1.
  **
  ** ^If the progress callback returns non-zero, the operation is
  ** interrupted.  This feature can be used to implement a
  ** "Cancel" button on a GUI progress dialog box.
  **
  ** The progress handler callback must not do anything that will modify
  ** the database connection that invoked the progress handler.
  ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
  ** database connections for the meaning of "modify" in this paragraph.
  **
  */
  SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
  
  /*
  ** CAPI3REF: Opening A New Database Connection
  ** CONSTRUCTOR: sqlite3
  **
  ** ^These routines open an SQLite database file as specified by the
  ** filename argument. ^The filename argument is interpreted as UTF-8 for
  ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
  ** order for sqlite3_open16(). ^(A [database connection] handle is usually
  ** returned in *ppDb, even if an error occurs.  The only exception is that
  ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
  ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
  ** object.)^ ^(If the database is opened (and/or created) successfully, then
  ** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
  ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
  ** an English language description of the error following a failure of any
  ** of the sqlite3_open() routines.
  **
  ** ^The default encoding will be UTF-8 for databases created using
  ** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
  ** created using sqlite3_open16() will be UTF-16 in the native byte order.
  **
  ** Whether or not an error occurs when it is opened, resources
  ** associated with the [database connection] handle should be released by
  ** passing it to [sqlite3_close()] when it is no longer required.
  **
  ** The sqlite3_open_v2() interface works like sqlite3_open()
  ** except that it accepts two additional parameters for additional control
  ** over the new database connection.  ^(The flags parameter to
  ** sqlite3_open_v2() must include, at a minimum, one of the following
  ** three flag combinations:)^
  **
  ** <dl>
  ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
  ** <dd>The database is opened in read-only mode.  If the database does not
  ** already exist, an error is returned.</dd>)^
  **
  ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
  ** <dd>The database is opened for reading and writing if possible, or reading
  ** only if the file is write protected by the operating system.  In either
  ** case the database must already exist, otherwise an error is returned.</dd>)^
  **
  ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
  ** <dd>The database is opened for reading and writing, and is created if
  ** it does not already exist. This is the behavior that is always used for
  ** sqlite3_open() and sqlite3_open16().</dd>)^
  ** </dl>
  **
  ** In addition to the required flags, the following optional flags are
  ** also supported:
  **
  ** <dl>
  ** ^(<dt>[SQLITE_OPEN_URI]</dt>
  ** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^
  **
  ** ^(<dt>[SQLITE_OPEN_MEMORY]</dt>
  ** <dd>The database will be opened as an in-memory database.  The database
  ** is named by the "filename" argument for the purposes of cache-sharing,
  ** if shared cache mode is enabled, but the "filename" is otherwise ignored.
  ** </dd>)^
  **
  ** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt>
  ** <dd>The new database connection will use the "multi-thread"
  ** [threading mode].)^  This means that separate threads are allowed
  ** to use SQLite at the same time, as long as each thread is using
  ** a different [database connection].
  **
  ** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt>
  ** <dd>The new database connection will use the "serialized"
  ** [threading mode].)^  This means the multiple threads can safely
  ** attempt to use the same database connection at the same time.
  ** (Mutexes will block any actual concurrency, but in this mode
  ** there is no harm in trying.)
  **
  ** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt>
  ** <dd>The database is opened [shared cache] enabled, overriding
  ** the default shared cache setting provided by
  ** [sqlite3_enable_shared_cache()].)^
  **
  ** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt>
  ** <dd>The database is opened [shared cache] disabled, overriding
  ** the default shared cache setting provided by
  ** [sqlite3_enable_shared_cache()].)^
  **
  ** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt>
  ** <dd>The database filename is not allowed to be a symbolic link</dd>
  ** </dl>)^
  **
  ** If the 3rd parameter to sqlite3_open_v2() is not one of the
  ** required combinations shown above optionally combined with other
  ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
  ** then the behavior is undefined.
  **
  ** ^The fourth parameter to sqlite3_open_v2() is the name of the
  ** [sqlite3_vfs] object that defines the operating system interface that
  ** the new database connection should use.  ^If the fourth parameter is
  ** a NULL pointer then the default [sqlite3_vfs] object is used.
  **
  ** ^If the filename is ":memory:", then a private, temporary in-memory database
  ** is created for the connection.  ^This in-memory database will vanish when
  ** the database connection is closed.  Future versions of SQLite might
  ** make use of additional special filenames that begin with the ":" character.
  ** It is recommended that when a database filename actually does begin with
  ** a ":" character you should prefix the filename with a pathname such as
  ** "./" to avoid ambiguity.
  **
  ** ^If the filename is an empty string, then a private, temporary
  ** on-disk database will be created.  ^This private database will be
  ** automatically deleted as soon as the database connection is closed.
  **
  ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
  **
  ** ^If [URI filename] interpretation is enabled, and the filename argument
  ** begins with "file:", then the filename is interpreted as a URI. ^URI
  ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
  ** set in the third argument to sqlite3_open_v2(), or if it has
  ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
  ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
  ** URI filename interpretation is turned off
  ** by default, but future releases of SQLite might enable URI filename
  ** interpretation by default.  See "[URI filenames]" for additional
  ** information.
  **
  ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
  ** authority, then it must be either an empty string or the string
  ** "localhost". ^If the authority is not an empty string or "localhost", an
  ** error is returned to the caller. ^The fragment component of a URI, if
  ** present, is ignored.
  **
  ** ^SQLite uses the path component of the URI as the name of the disk file
  ** which contains the database. ^If the path begins with a '/' character,
  ** then it is interpreted as an absolute path. ^If the path does not begin
  ** with a '/' (meaning that the authority section is omitted from the URI)
  ** then the path is interpreted as a relative path.
  ** ^(On windows, the first component of an absolute path
  ** is a drive specification (e.g. "C:").)^
  **
  ** [[core URI query parameters]]
  ** The query component of a URI may contain parameters that are interpreted
  ** either by SQLite itself, or by a [VFS | custom VFS implementation].
  ** SQLite and its built-in [VFSes] interpret the
  ** following query parameters:
  **
  ** <ul>
  **   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
  **     a VFS object that provides the operating system interface that should
  **     be used to access the database file on disk. ^If this option is set to
  **     an empty string the default VFS object is used. ^Specifying an unknown
  **     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
  **     present, then the VFS specified by the option takes precedence over
  **     the value passed as the fourth parameter to sqlite3_open_v2().
  **
  **   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
  **     "rwc", or "memory". Attempting to set it to any other value is
  **     an error)^.
  **     ^If "ro" is specified, then the database is opened for read-only
  **     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
  **     third argument to sqlite3_open_v2(). ^If the mode option is set to
  **     "rw", then the database is opened for read-write (but not create)
  **     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
  **     been set. ^Value "rwc" is equivalent to setting both
  **     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
  **     set to "memory" then a pure [in-memory database] that never reads
  **     or writes from disk is used. ^It is an error to specify a value for
  **     the mode parameter that is less restrictive than that specified by
  **     the flags passed in the third parameter to sqlite3_open_v2().
  **
  **   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
  **     "private". ^Setting it to "shared" is equivalent to setting the
  **     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
  **     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
  **     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
  **     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
  **     a URI filename, its value overrides any behavior requested by setting
  **     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
  **
  **  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
  **     [powersafe overwrite] property does or does not apply to the
  **     storage media on which the database file resides.
  **
  **  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
  **     which if set disables file locking in rollback journal modes.  This
  **     is useful for accessing a database on a filesystem that does not
  **     support locking.  Caution:  Database corruption might result if two
  **     or more processes write to the same database and any one of those
  **     processes uses nolock=1.
  **
  **  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
  **     parameter that indicates that the database file is stored on
  **     read-only media.  ^When immutable is set, SQLite assumes that the
  **     database file cannot be changed, even by a process with higher
  **     privilege, and so the database is opened read-only and all locking
  **     and change detection is disabled.  Caution: Setting the immutable
  **     property on a database file that does in fact change can result
  **     in incorrect query results and/or [SQLITE_CORRUPT] errors.
  **     See also: [SQLITE_IOCAP_IMMUTABLE].
  **
  ** </ul>
  **
  ** ^Specifying an unknown parameter in the query component of a URI is not an
  ** error.  Future versions of SQLite might understand additional query
  ** parameters.  See "[query parameters with special meaning to SQLite]" for
  ** additional information.
  **
  ** [[URI filename examples]] <h3>URI filename examples</h3>
  **
  ** <table border="1" align=center cellpadding=5>
  ** <tr><th> URI filenames <th> Results
  ** <tr><td> file:data.db <td>
  **          Open the file "data.db" in the current directory.
  ** <tr><td> file:/home/fred/data.db<br>
  **          file:///home/fred/data.db <br>
  **          file://localhost/home/fred/data.db <br> <td>
  **          Open the database file "/home/fred/data.db".
  ** <tr><td> file://darkstar/home/fred/data.db <td>
  **          An error. "darkstar" is not a recognized authority.
  ** <tr><td style="white-space:nowrap">
  **          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
  **     <td> Windows only: Open the file "data.db" on fred's desktop on drive
  **          C:. Note that the %20 escaping in this example is not strictly
  **          necessary - space characters can be used literally
  **          in URI filenames.
  ** <tr><td> file:data.db?mode=ro&cache=private <td>
  **          Open file "data.db" in the current directory for read-only access.
  **          Regardless of whether or not shared-cache mode is enabled by
  **          default, use a private cache.
  ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
  **          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
  **          that uses dot-files in place of posix advisory locking.
  ** <tr><td> file:data.db?mode=readonly <td>
  **          An error. "readonly" is not a valid option for the "mode" parameter.
  ** </table>
  **
  ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
  ** query components of a URI. A hexadecimal escape sequence consists of a
  ** percent sign - "%" - followed by exactly two hexadecimal digits
  ** specifying an octet value. ^Before the path or query components of a
  ** URI filename are interpreted, they are encoded using UTF-8 and all
  ** hexadecimal escape sequences replaced by a single byte containing the
  ** corresponding octet. If this process generates an invalid UTF-8 encoding,
  ** the results are undefined.
  **
  ** <b>Note to Windows users:</b>  The encoding used for the filename argument
  ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
  ** codepage is currently defined.  Filenames containing international
  ** characters must be converted to UTF-8 prior to passing them into
  ** sqlite3_open() or sqlite3_open_v2().
  **
  ** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
  ** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
  ** features that require the use of temporary files may fail.
  **
  ** See also: [sqlite3_temp_directory]
  */
  SQLITE_API int sqlite3_open(
    const char *filename,   /* Database filename (UTF-8) */
    sqlite3 **ppDb          /* OUT: SQLite db handle */
  );
  SQLITE_API int sqlite3_open16(
    const void *filename,   /* Database filename (UTF-16) */
    sqlite3 **ppDb          /* OUT: SQLite db handle */
  );
  SQLITE_API int sqlite3_open_v2(
    const char *filename,   /* Database filename (UTF-8) */
    sqlite3 **ppDb,         /* OUT: SQLite db handle */
    int flags,              /* Flags */
    const char *zVfs        /* Name of VFS module to use */
  );
  
  /*
  ** CAPI3REF: Obtain Values For URI Parameters
  **
  ** These are utility routines, useful to [VFS|custom VFS implementations],
  ** that check if a database file was a URI that contained a specific query
  ** parameter, and if so obtains the value of that query parameter.
  **
  ** The first parameter to these interfaces (hereafter referred to
  ** as F) must be one of:
  ** <ul>
  ** <li> A database filename pointer created by the SQLite core and
  ** passed into the xOpen() method of a VFS implemention, or
  ** <li> A filename obtained from [sqlite3_db_filename()], or
  ** <li> A new filename constructed using [sqlite3_create_filename()].
  ** </ul>
  ** If the F parameter is not one of the above, then the behavior is
  ** undefined and probably undesirable.  Older versions of SQLite were
  ** more tolerant of invalid F parameters than newer versions.
  **
  ** If F is a suitable filename (as described in the previous paragraph)
  ** and if P is the name of the query parameter, then
  ** sqlite3_uri_parameter(F,P) returns the value of the P
  ** parameter if it exists or a NULL pointer if P does not appear as a
  ** query parameter on F.  If P is a query parameter of F and it
  ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
  ** a pointer to an empty string.
  **
  ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
  ** parameter and returns true (1) or false (0) according to the value
  ** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
  ** value of query parameter P is one of "yes", "true", or "on" in any
  ** case or if the value begins with a non-zero number.  The
  ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
  ** query parameter P is one of "no", "false", or "off" in any case or
  ** if the value begins with a numeric zero.  If P is not a query
  ** parameter on F or if the value of P does not match any of the
  ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
  **
  ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
  ** 64-bit signed integer and returns that integer, or D if P does not
  ** exist.  If the value of P is something other than an integer, then
  ** zero is returned.
  **
  ** The sqlite3_uri_key(F,N) returns a pointer to the name (not
  ** the value) of the N-th query parameter for filename F, or a NULL
  ** pointer if N is less than zero or greater than the number of query
  ** parameters minus 1.  The N value is zero-based so N should be 0 to obtain
  ** the name of the first query parameter, 1 for the second parameter, and
  ** so forth.
  **
  ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
  ** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
  ** is not a database file pathname pointer that the SQLite core passed
  ** into the xOpen VFS method, then the behavior of this routine is undefined
  ** and probably undesirable.
  **
  ** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F
  ** parameter can also be the name of a rollback journal file or WAL file
  ** in addition to the main database file.  Prior to version 3.31.0, these
  ** routines would only work if F was the name of the main database file.
  ** When the F parameter is the name of the rollback journal or WAL file,
  ** it has access to all the same query parameters as were found on the
  ** main database file.
  **
  ** See the [URI filename] documentation for additional information.
  */
  SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
  SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
  SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
  SQLITE_API const char *sqlite3_uri_key(const char *zFilename, int N);
  
  /*
  ** CAPI3REF:  Translate filenames
  **
  ** These routines are available to [VFS|custom VFS implementations] for
  ** translating filenames between the main database file, the journal file,
  ** and the WAL file.
  **
  ** If F is the name of an sqlite database file, journal file, or WAL file
  ** passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
  ** returns the name of the corresponding database file.
  **
  ** If F is the name of an sqlite database file, journal file, or WAL file
  ** passed by the SQLite core into the VFS, or if F is a database filename
  ** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F)
  ** returns the name of the corresponding rollback journal file.
  **
  ** If F is the name of an sqlite database file, journal file, or WAL file
  ** that was passed by the SQLite core into the VFS, or if F is a database
  ** filename obtained from [sqlite3_db_filename()], then
  ** sqlite3_filename_wal(F) returns the name of the corresponding
  ** WAL file.
  **
  ** In all of the above, if F is not the name of a database, journal or WAL
  ** filename passed into the VFS from the SQLite core and F is not the
  ** return value from [sqlite3_db_filename()], then the result is
  ** undefined and is likely a memory access violation.
  */
  SQLITE_API const char *sqlite3_filename_database(const char*);
  SQLITE_API const char *sqlite3_filename_journal(const char*);
  SQLITE_API const char *sqlite3_filename_wal(const char*);
  
  /*
  ** CAPI3REF:  Database File Corresponding To A Journal
  **
  ** ^If X is the name of a rollback or WAL-mode journal file that is
  ** passed into the xOpen method of [sqlite3_vfs], then
  ** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file]
  ** object that represents the main database file.
  **
  ** This routine is intended for use in custom [VFS] implementations
  ** only.  It is not a general-purpose interface.
  ** The argument sqlite3_file_object(X) must be a filename pointer that
  ** has been passed into [sqlite3_vfs].xOpen method where the
  ** flags parameter to xOpen contains one of the bits
  ** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL].  Any other use
  ** of this routine results in undefined and probably undesirable
  ** behavior.
  */
  SQLITE_API sqlite3_file *sqlite3_database_file_object(const char*);
  
  /*
  ** CAPI3REF: Create and Destroy VFS Filenames
  **
  ** These interfces are provided for use by [VFS shim] implementations and
  ** are not useful outside of that context.
  **
  ** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
  ** database filename D with corresponding journal file J and WAL file W and
  ** with N URI parameters key/values pairs in the array P.  The result from
  ** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
  ** is safe to pass to routines like:
  ** <ul>
  ** <li> [sqlite3_uri_parameter()],
  ** <li> [sqlite3_uri_boolean()],
  ** <li> [sqlite3_uri_int64()],
  ** <li> [sqlite3_uri_key()],
  ** <li> [sqlite3_filename_database()],
  ** <li> [sqlite3_filename_journal()], or
  ** <li> [sqlite3_filename_wal()].
  ** </ul>
  ** If a memory allocation error occurs, sqlite3_create_filename() might
  ** return a NULL pointer.  The memory obtained from sqlite3_create_filename(X)
  ** must be released by a corresponding call to sqlite3_free_filename(Y).
  **
  ** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
  ** of 2*N pointers to strings.  Each pair of pointers in this array corresponds
  ** to a key and value for a query parameter.  The P parameter may be a NULL
  ** pointer if N is zero.  None of the 2*N pointers in the P array may be
  ** NULL pointers and key pointers should not be empty strings.
  ** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
  ** be NULL pointers, though they can be empty strings.
  **
  ** The sqlite3_free_filename(Y) routine releases a memory allocation
  ** previously obtained from sqlite3_create_filename().  Invoking
  ** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.
  **
  ** If the Y parameter to sqlite3_free_filename(Y) is anything other
  ** than a NULL pointer or a pointer previously acquired from
  ** sqlite3_create_filename(), then bad things such as heap
  ** corruption or segfaults may occur. The value Y should not be
  ** used again after sqlite3_free_filename(Y) has been called.  This means
  ** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y,
  ** then the corresponding [sqlite3_module.xClose() method should also be
  ** invoked prior to calling sqlite3_free_filename(Y).
  */
  SQLITE_API char *sqlite3_create_filename(
    const char *zDatabase,
    const char *zJournal,
    const char *zWal,
    int nParam,
    const char **azParam
  );
  SQLITE_API void sqlite3_free_filename(char*);
  
  /*
  ** CAPI3REF: Error Codes And Messages
  ** METHOD: sqlite3
  **
  ** ^If the most recent sqlite3_* API call associated with
  ** [database connection] D failed, then the sqlite3_errcode(D) interface
  ** returns the numeric [result code] or [extended result code] for that
  ** API call.
  ** ^The sqlite3_extended_errcode()
  ** interface is the same except that it always returns the
  ** [extended result code] even when extended result codes are
  ** disabled.
  **
  ** The values returned by sqlite3_errcode() and/or
  ** sqlite3_extended_errcode() might change with each API call.
  ** Except, there are some interfaces that are guaranteed to never
  ** change the value of the error code.  The error-code preserving
  ** interfaces are:
  **
  ** <ul>
  ** <li> sqlite3_errcode()
  ** <li> sqlite3_extended_errcode()
  ** <li> sqlite3_errmsg()
  ** <li> sqlite3_errmsg16()
  ** </ul>
  **
  ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
  ** text that describes the error, as either UTF-8 or UTF-16 respectively.
  ** ^(Memory to hold the error message string is managed internally.
  ** The application does not need to worry about freeing the result.
  ** However, the error string might be overwritten or deallocated by
  ** subsequent calls to other SQLite interface functions.)^
  **
  ** ^The sqlite3_errstr() interface returns the English-language text
  ** that describes the [result code], as UTF-8.
  ** ^(Memory to hold the error message string is managed internally
  ** and must not be freed by the application)^.
  **
  ** When the serialized [threading mode] is in use, it might be the
  ** case that a second error occurs on a separate thread in between
  ** the time of the first error and the call to these interfaces.
  ** When that happens, the second error will be reported since these
  ** interfaces always report the most recent result.  To avoid
  ** this, each thread can obtain exclusive use of the [database connection] D
  ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
  ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
  ** all calls to the interfaces listed here are completed.
  **
  ** If an interface fails with SQLITE_MISUSE, that means the interface
  ** was invoked incorrectly by the application.  In that case, the
  ** error code and message may or may not be set.
  */
  SQLITE_API int sqlite3_errcode(sqlite3 *db);
  SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
  SQLITE_API const char *sqlite3_errmsg(sqlite3*);
  SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
  SQLITE_API const char *sqlite3_errstr(int);
  
  /*
  ** CAPI3REF: Prepared Statement Object
  ** KEYWORDS: {prepared statement} {prepared statements}
  **
  ** An instance of this object represents a single SQL statement that
  ** has been compiled into binary form and is ready to be evaluated.
  **
  ** Think of each SQL statement as a separate computer program.  The
  ** original SQL text is source code.  A prepared statement object
  ** is the compiled object code.  All SQL must be converted into a
  ** prepared statement before it can be run.
  **
  ** The life-cycle of a prepared statement object usually goes like this:
  **
  ** <ol>
  ** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
  ** <li> Bind values to [parameters] using the sqlite3_bind_*()
  **      interfaces.
  ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
  ** <li> Reset the prepared statement using [sqlite3_reset()] then go back
  **      to step 2.  Do this zero or more times.
  ** <li> Destroy the object using [sqlite3_finalize()].
  ** </ol>
  */
  typedef struct sqlite3_stmt sqlite3_stmt;
  
  /*
  ** CAPI3REF: Run-time Limits
  ** METHOD: sqlite3
  **
  ** ^(This interface allows the size of various constructs to be limited
  ** on a connection by connection basis.  The first parameter is the
  ** [database connection] whose limit is to be set or queried.  The
  ** second parameter is one of the [limit categories] that define a
  ** class of constructs to be size limited.  The third parameter is the
  ** new limit for that construct.)^
  **
  ** ^If the new limit is a negative number, the limit is unchanged.
  ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
  ** [limits | hard upper bound]
  ** set at compile-time by a C preprocessor macro called
  ** [limits | SQLITE_MAX_<i>NAME</i>].
  ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
  ** ^Attempts to increase a limit above its hard upper bound are
  ** silently truncated to the hard upper bound.
  **
  ** ^Regardless of whether or not the limit was changed, the
  ** [sqlite3_limit()] interface returns the prior value of the limit.
  ** ^Hence, to find the current value of a limit without changing it,
  ** simply invoke this interface with the third parameter set to -1.
  **
  ** Run-time limits are intended for use in applications that manage
  ** both their own internal database and also databases that are controlled
  ** by untrusted external sources.  An example application might be a
  ** web browser that has its own databases for storing history and
  ** separate databases controlled by JavaScript applications downloaded
  ** off the Internet.  The internal databases can be given the
  ** large, default limits.  Databases managed by external sources can
  ** be given much smaller limits designed to prevent a denial of service
  ** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
  ** interface to further control untrusted SQL.  The size of the database
  ** created by an untrusted script can be contained using the
  ** [max_page_count] [PRAGMA].
  **
  ** New run-time limit categories may be added in future releases.
  */
  SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
  
  /*
  ** CAPI3REF: Run-Time Limit Categories
  ** KEYWORDS: {limit category} {*limit categories}
  **
  ** These constants define various performance limits
  ** that can be lowered at run-time using [sqlite3_limit()].
  ** The synopsis of the meanings of the various limits is shown below.
  ** Additional information is available at [limits | Limits in SQLite].
  **
  ** <dl>
  ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
  ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
  **
  ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
  ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
  **
  ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
  ** <dd>The maximum number of columns in a table definition or in the
  ** result set of a [SELECT] or the maximum number of columns in an index
  ** or in an ORDER BY or GROUP BY clause.</dd>)^
  **
  ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
  ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
  **
  ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
  ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
  **
  ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
  ** <dd>The maximum number of instructions in a virtual machine program
  ** used to implement an SQL statement.  If [sqlite3_prepare_v2()] or
  ** the equivalent tries to allocate space for more than this many opcodes
  ** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
  **
  ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
  ** <dd>The maximum number of arguments on a function.</dd>)^
  **
  ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
  ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
  **
  ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
  ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
  ** <dd>The maximum length of the pattern argument to the [LIKE] or
  ** [GLOB] operators.</dd>)^
  **
  ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
  ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
  ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
  **
  ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
  ** <dd>The maximum depth of recursion for triggers.</dd>)^
  **
  ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
  ** <dd>The maximum number of auxiliary worker threads that a single
  ** [prepared statement] may start.</dd>)^
  ** </dl>
  */
  #define SQLITE_LIMIT_LENGTH                    0
  #define SQLITE_LIMIT_SQL_LENGTH                1
  #define SQLITE_LIMIT_COLUMN                    2
  #define SQLITE_LIMIT_EXPR_DEPTH                3
  #define SQLITE_LIMIT_COMPOUND_SELECT           4
  #define SQLITE_LIMIT_VDBE_OP                   5
  #define SQLITE_LIMIT_FUNCTION_ARG              6
  #define SQLITE_LIMIT_ATTACHED                  7
  #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
  #define SQLITE_LIMIT_VARIABLE_NUMBER           9
  #define SQLITE_LIMIT_TRIGGER_DEPTH            10
  #define SQLITE_LIMIT_WORKER_THREADS           11
  
  /*
  ** CAPI3REF: Prepare Flags
  **
  ** These constants define various flags that can be passed into
  ** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
  ** [sqlite3_prepare16_v3()] interfaces.
  **
  ** New flags may be added in future releases of SQLite.
  **
  ** <dl>
  ** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
  ** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
  ** that the prepared statement will be retained for a long time and
  ** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
  ** and [sqlite3_prepare16_v3()] assume that the prepared statement will
  ** be used just once or at most a few times and then destroyed using
  ** [sqlite3_finalize()] relatively soon. The current implementation acts
  ** on this hint by avoiding the use of [lookaside memory] so as not to
  ** deplete the limited store of lookaside memory. Future versions of
  ** SQLite may act on this hint differently.
  **
  ** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
  ** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
  ** to be required for any prepared statement that wanted to use the
  ** [sqlite3_normalized_sql()] interface.  However, the
  ** [sqlite3_normalized_sql()] interface is now available to all
  ** prepared statements, regardless of whether or not they use this
  ** flag.
  **
  ** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt>
  ** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
  ** to return an error (error code SQLITE_ERROR) if the statement uses
  ** any virtual tables.
  ** </dl>
  */
  #define SQLITE_PREPARE_PERSISTENT              0x01
  #define SQLITE_PREPARE_NORMALIZE               0x02
  #define SQLITE_PREPARE_NO_VTAB                 0x04
  
  /*
  ** CAPI3REF: Compiling An SQL Statement
  ** KEYWORDS: {SQL statement compiler}
  ** METHOD: sqlite3
  ** CONSTRUCTOR: sqlite3_stmt
  **
  ** To execute an SQL statement, it must first be compiled into a byte-code
  ** program using one of these routines.  Or, in other words, these routines
  ** are constructors for the [prepared statement] object.
  **
  ** The preferred routine to use is [sqlite3_prepare_v2()].  The
  ** [sqlite3_prepare()] interface is legacy and should be avoided.
  ** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
  ** for special purposes.
  **
  ** The use of the UTF-8 interfaces is preferred, as SQLite currently
  ** does all parsing using UTF-8.  The UTF-16 interfaces are provided
  ** as a convenience.  The UTF-16 interfaces work by converting the
  ** input text into UTF-8, then invoking the corresponding UTF-8 interface.
  **
  ** The first argument, "db", is a [database connection] obtained from a
  ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
  ** [sqlite3_open16()].  The database connection must not have been closed.
  **
  ** The second argument, "zSql", is the statement to be compiled, encoded
  ** as either UTF-8 or UTF-16.  The sqlite3_prepare(), sqlite3_prepare_v2(),
  ** and sqlite3_prepare_v3()
  ** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
  ** and sqlite3_prepare16_v3() use UTF-16.
  **
  ** ^If the nByte argument is negative, then zSql is read up to the
  ** first zero terminator. ^If nByte is positive, then it is the
  ** number of bytes read from zSql.  ^If nByte is zero, then no prepared
  ** statement is generated.
  ** If the caller knows that the supplied string is nul-terminated, then
  ** there is a small performance advantage to passing an nByte parameter that
  ** is the number of bytes in the input string <i>including</i>
  ** the nul-terminator.
  **
  ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
  ** past the end of the first SQL statement in zSql.  These routines only
  ** compile the first statement in zSql, so *pzTail is left pointing to
  ** what remains uncompiled.
  **
  ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
  ** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
  ** to NULL.  ^If the input text contains no SQL (if the input is an empty
  ** string or a comment) then *ppStmt is set to NULL.
  ** The calling procedure is responsible for deleting the compiled
  ** SQL statement using [sqlite3_finalize()] after it has finished with it.
  ** ppStmt may not be NULL.
  **
  ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
  ** otherwise an [error code] is returned.
  **
  ** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
  ** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
  ** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
  ** are retained for backwards compatibility, but their use is discouraged.
  ** ^In the "vX" interfaces, the prepared statement
  ** that is returned (the [sqlite3_stmt] object) contains a copy of the
  ** original SQL text. This causes the [sqlite3_step()] interface to
  ** behave differently in three ways:
  **
  ** <ol>
  ** <li>
  ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
  ** always used to do, [sqlite3_step()] will automatically recompile the SQL
  ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
  ** retries will occur before sqlite3_step() gives up and returns an error.
  ** </li>
  **
  ** <li>
  ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
  ** [error codes] or [extended error codes].  ^The legacy behavior was that
  ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
  ** and the application would have to make a second call to [sqlite3_reset()]
  ** in order to find the underlying cause of the problem. With the "v2" prepare
  ** interfaces, the underlying reason for the error is returned immediately.
  ** </li>
  **
  ** <li>
  ** ^If the specific value bound to a [parameter | host parameter] in the
  ** WHERE clause might influence the choice of query plan for a statement,
  ** then the statement will be automatically recompiled, as if there had been
  ** a schema change, on the first [sqlite3_step()] call following any change
  ** to the [sqlite3_bind_text | bindings] of that [parameter].
  ** ^The specific value of a WHERE-clause [parameter] might influence the
  ** choice of query plan if the parameter is the left-hand side of a [LIKE]
  ** or [GLOB] operator or if the parameter is compared to an indexed column
  ** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled.
  ** </li>
  ** </ol>
  **
  ** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
  ** the extra prepFlags parameter, which is a bit array consisting of zero or
  ** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags.  ^The
  ** sqlite3_prepare_v2() interface works exactly the same as
  ** sqlite3_prepare_v3() with a zero prepFlags parameter.
  */
  SQLITE_API int sqlite3_prepare(
    sqlite3 *db,            /* Database handle */
    const char *zSql,       /* SQL statement, UTF-8 encoded */
    int nByte,              /* Maximum length of zSql in bytes. */
    sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
    const char **pzTail     /* OUT: Pointer to unused portion of zSql */
  );
  SQLITE_API int sqlite3_prepare_v2(
    sqlite3 *db,            /* Database handle */
    const char *zSql,       /* SQL statement, UTF-8 encoded */
    int nByte,              /* Maximum length of zSql in bytes. */
    sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
    const char **pzTail     /* OUT: Pointer to unused portion of zSql */
  );
  SQLITE_API int sqlite3_prepare_v3(
    sqlite3 *db,            /* Database handle */
    const char *zSql,       /* SQL statement, UTF-8 encoded */
    int nByte,              /* Maximum length of zSql in bytes. */
    unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
    sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
    const char **pzTail     /* OUT: Pointer to unused portion of zSql */
  );
  SQLITE_API int sqlite3_prepare16(
    sqlite3 *db,            /* Database handle */
    const void *zSql,       /* SQL statement, UTF-16 encoded */
    int nByte,              /* Maximum length of zSql in bytes. */
    sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
    const void **pzTail     /* OUT: Pointer to unused portion of zSql */
  );
  SQLITE_API int sqlite3_prepare16_v2(
    sqlite3 *db,            /* Database handle */
    const void *zSql,       /* SQL statement, UTF-16 encoded */
    int nByte,              /* Maximum length of zSql in bytes. */
    sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
    const void **pzTail     /* OUT: Pointer to unused portion of zSql */
  );
  SQLITE_API int sqlite3_prepare16_v3(
    sqlite3 *db,            /* Database handle */
    const void *zSql,       /* SQL statement, UTF-16 encoded */
    int nByte,              /* Maximum length of zSql in bytes. */
    unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
    sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
    const void **pzTail     /* OUT: Pointer to unused portion of zSql */
  );
  
  /*
  ** CAPI3REF: Retrieving Statement SQL
  ** METHOD: sqlite3_stmt
  **
  ** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
  ** SQL text used to create [prepared statement] P if P was
  ** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
  ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
  ** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
  ** string containing the SQL text of prepared statement P with
  ** [bound parameters] expanded.
  ** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
  ** string containing the normalized SQL text of prepared statement P.  The
  ** semantics used to normalize a SQL statement are unspecified and subject
  ** to change.  At a minimum, literal values will be replaced with suitable
  ** placeholders.
  **
  ** ^(For example, if a prepared statement is created using the SQL
  ** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
  ** and parameter :xyz is unbound, then sqlite3_sql() will return
  ** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
  ** will return "SELECT 2345,NULL".)^
  **
  ** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
  ** is available to hold the result, or if the result would exceed the
  ** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
  **
  ** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
  ** bound parameter expansions.  ^The [SQLITE_OMIT_TRACE] compile-time
  ** option causes sqlite3_expanded_sql() to always return NULL.
  **
  ** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
  ** are managed by SQLite and are automatically freed when the prepared
  ** statement is finalized.
  ** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
  ** is obtained from [sqlite3_malloc()] and must be free by the application
  ** by passing it to [sqlite3_free()].
  */
  SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
  SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
  SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
  
  /*
  ** CAPI3REF: Determine If An SQL Statement Writes The Database
  ** METHOD: sqlite3_stmt
  **
  ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
  ** and only if the [prepared statement] X makes no direct changes to
  ** the content of the database file.
  **
  ** Note that [application-defined SQL functions] or
  ** [virtual tables] might change the database indirectly as a side effect.
  ** ^(For example, if an application defines a function "eval()" that
  ** calls [sqlite3_exec()], then the following SQL statement would
  ** change the database file through side-effects:
  **
  ** <blockquote><pre>
  **    SELECT eval('DELETE FROM t1') FROM t2;
  ** </pre></blockquote>
  **
  ** But because the [SELECT] statement does not change the database file
  ** directly, sqlite3_stmt_readonly() would still return true.)^
  **
  ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
  ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
  ** since the statements themselves do not actually modify the database but
  ** rather they control the timing of when other statements modify the
  ** database.  ^The [ATTACH] and [DETACH] statements also cause
  ** sqlite3_stmt_readonly() to return true since, while those statements
  ** change the configuration of a database connection, they do not make
  ** changes to the content of the database files on disk.
  ** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
  ** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
  ** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
  ** sqlite3_stmt_readonly() returns false for those commands.
  */
  SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
  
  /*
  ** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
  ** METHOD: sqlite3_stmt
  **
  ** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
  ** prepared statement S is an EXPLAIN statement, or 2 if the
  ** statement S is an EXPLAIN QUERY PLAN.
  ** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
  ** an ordinary statement or a NULL pointer.
  */
  SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
  
  /*
  ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
  ** METHOD: sqlite3_stmt
  **
  ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
  ** [prepared statement] S has been stepped at least once using
  ** [sqlite3_step(S)] but has neither run to completion (returned
  ** [SQLITE_DONE] from [sqlite3_step(S)]) nor
  ** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
  ** interface returns false if S is a NULL pointer.  If S is not a
  ** NULL pointer and is not a pointer to a valid [prepared statement]
  ** object, then the behavior is undefined and probably undesirable.
  **
  ** This interface can be used in combination [sqlite3_next_stmt()]
  ** to locate all prepared statements associated with a database
  ** connection that are in need of being reset.  This can be used,
  ** for example, in diagnostic routines to search for prepared
  ** statements that are holding a transaction open.
  */
  SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
  
  /*
  ** CAPI3REF: Dynamically Typed Value Object
  ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
  **
  ** SQLite uses the sqlite3_value object to represent all values
  ** that can be stored in a database table. SQLite uses dynamic typing
  ** for the values it stores.  ^Values stored in sqlite3_value objects
  ** can be integers, floating point values, strings, BLOBs, or NULL.
  **
  ** An sqlite3_value object may be either "protected" or "unprotected".
  ** Some interfaces require a protected sqlite3_value.  Other interfaces
  ** will accept either a protected or an unprotected sqlite3_value.
  ** Every interface that accepts sqlite3_value arguments specifies
  ** whether or not it requires a protected sqlite3_value.  The
  ** [sqlite3_value_dup()] interface can be used to construct a new
  ** protected sqlite3_value from an unprotected sqlite3_value.
  **
  ** The terms "protected" and "unprotected" refer to whether or not
  ** a mutex is held.  An internal mutex is held for a protected
  ** sqlite3_value object but no mutex is held for an unprotected
  ** sqlite3_value object.  If SQLite is compiled to be single-threaded
  ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
  ** or if SQLite is run in one of reduced mutex modes
  ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
  ** then there is no distinction between protected and unprotected
  ** sqlite3_value objects and they can be used interchangeably.  However,
  ** for maximum code portability it is recommended that applications
  ** still make the distinction between protected and unprotected
  ** sqlite3_value objects even when not strictly required.
  **
  ** ^The sqlite3_value objects that are passed as parameters into the
  ** implementation of [application-defined SQL functions] are protected.
  ** ^The sqlite3_value object returned by
  ** [sqlite3_column_value()] is unprotected.
  ** Unprotected sqlite3_value objects may only be used as arguments
  ** to [sqlite3_result_value()], [sqlite3_bind_value()], and
  ** [sqlite3_value_dup()].
  ** The [sqlite3_value_blob | sqlite3_value_type()] family of
  ** interfaces require protected sqlite3_value objects.
  */
  typedef struct sqlite3_value sqlite3_value;
  
  /*
  ** CAPI3REF: SQL Function Context Object
  **
  ** The context in which an SQL function executes is stored in an
  ** sqlite3_context object.  ^A pointer to an sqlite3_context object
  ** is always first parameter to [application-defined SQL functions].
  ** The application-defined SQL function implementation will pass this
  ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
  ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
  ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
  ** and/or [sqlite3_set_auxdata()].
  */
  typedef struct sqlite3_context sqlite3_context;
  
  /*
  ** CAPI3REF: Binding Values To Prepared Statements
  ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
  ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
  ** METHOD: sqlite3_stmt
  **
  ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
  ** literals may be replaced by a [parameter] that matches one of following
  ** templates:
  **
  ** <ul>
  ** <li>  ?
  ** <li>  ?NNN
  ** <li>  :VVV
  ** <li>  @VVV
  ** <li>  $VVV
  ** </ul>
  **
  ** In the templates above, NNN represents an integer literal,
  ** and VVV represents an alphanumeric identifier.)^  ^The values of these
  ** parameters (also called "host parameter names" or "SQL parameters")
  ** can be set using the sqlite3_bind_*() routines defined here.
  **
  ** ^The first argument to the sqlite3_bind_*() routines is always
  ** a pointer to the [sqlite3_stmt] object returned from
  ** [sqlite3_prepare_v2()] or its variants.
  **
  ** ^The second argument is the index of the SQL parameter to be set.
  ** ^The leftmost SQL parameter has an index of 1.  ^When the same named
  ** SQL parameter is used more than once, second and subsequent
  ** occurrences have the same index as the first occurrence.
  ** ^The index for named parameters can be looked up using the
  ** [sqlite3_bind_parameter_index()] API if desired.  ^The index
  ** for "?NNN" parameters is the value of NNN.
  ** ^The NNN value must be between 1 and the [sqlite3_limit()]
  ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766).
  **
  ** ^The third argument is the value to bind to the parameter.
  ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
  ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
  ** is ignored and the end result is the same as sqlite3_bind_null().
  ** ^If the third parameter to sqlite3_bind_text() is not NULL, then
  ** it should be a pointer to well-formed UTF8 text.
  ** ^If the third parameter to sqlite3_bind_text16() is not NULL, then
  ** it should be a pointer to well-formed UTF16 text.
  ** ^If the third parameter to sqlite3_bind_text64() is not NULL, then
  ** it should be a pointer to a well-formed unicode string that is
  ** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16
  ** otherwise.
  **
  ** [[byte-order determination rules]] ^The byte-order of
  ** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
  ** found in first character, which is removed, or in the absence of a BOM
  ** the byte order is the native byte order of the host
  ** machine for sqlite3_bind_text16() or the byte order specified in
  ** the 6th parameter for sqlite3_bind_text64().)^
  ** ^If UTF16 input text contains invalid unicode
  ** characters, then SQLite might change those invalid characters
  ** into the unicode replacement character: U+FFFD.
  **
  ** ^(In those routines that have a fourth argument, its value is the
  ** number of bytes in the parameter.  To be clear: the value is the
  ** number of <u>bytes</u> in the value, not the number of characters.)^
  ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
  ** is negative, then the length of the string is
  ** the number of bytes up to the first zero terminator.
  ** If the fourth parameter to sqlite3_bind_blob() is negative, then
  ** the behavior is undefined.
  ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
  ** or sqlite3_bind_text16() or sqlite3_bind_text64() then
  ** that parameter must be the byte offset
  ** where the NUL terminator would occur assuming the string were NUL
  ** terminated.  If any NUL characters occurs at byte offsets less than
  ** the value of the fourth parameter then the resulting string value will
  ** contain embedded NULs.  The result of expressions involving strings
  ** with embedded NULs is undefined.
  **
  ** ^The fifth argument to the BLOB and string binding interfaces
  ** is a destructor used to dispose of the BLOB or
  ** string after SQLite has finished with it.  ^The destructor is called
  ** to dispose of the BLOB or string even if the call to the bind API fails,
  ** except the destructor is not called if the third parameter is a NULL
  ** pointer or the fourth parameter is negative.
  ** ^If the fifth argument is
  ** the special value [SQLITE_STATIC], then SQLite assumes that the
  ** information is in static, unmanaged space and does not need to be freed.
  ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
  ** SQLite makes its own private copy of the data immediately, before
  ** the sqlite3_bind_*() routine returns.
  **
  ** ^The sixth argument to sqlite3_bind_text64() must be one of
  ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
  ** to specify the encoding of the text in the third parameter.  If
  ** the sixth argument to sqlite3_bind_text64() is not one of the
  ** allowed values shown above, or if the text encoding is different
  ** from the encoding specified by the sixth parameter, then the behavior
  ** is undefined.
  **
  ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
  ** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
  ** (just an integer to hold its size) while it is being processed.
  ** Zeroblobs are intended to serve as placeholders for BLOBs whose
  ** content is later written using
  ** [sqlite3_blob_open | incremental BLOB I/O] routines.
  ** ^A negative value for the zeroblob results in a zero-length BLOB.
  **
  ** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
  ** [prepared statement] S to have an SQL value of NULL, but to also be
  ** associated with the pointer P of type T.  ^D is either a NULL pointer or
  ** a pointer to a destructor function for P. ^SQLite will invoke the
  ** destructor D with a single argument of P when it is finished using
  ** P.  The T parameter should be a static string, preferably a string
  ** literal. The sqlite3_bind_pointer() routine is part of the
  ** [pointer passing interface] added for SQLite 3.20.0.
  **
  ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
  ** for the [prepared statement] or with a prepared statement for which
  ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
  ** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
  ** routine is passed a [prepared statement] that has been finalized, the
  ** result is undefined and probably harmful.
  **
  ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
  ** ^Unbound parameters are interpreted as NULL.
  **
  ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
  ** [error code] if anything goes wrong.
  ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
  ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
  ** [SQLITE_MAX_LENGTH].
  ** ^[SQLITE_RANGE] is returned if the parameter
  ** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
  **
  ** See also: [sqlite3_bind_parameter_count()],
  ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
  */
  SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
  SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
                          void(*)(void*));
  SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
  SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
  SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
  SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
  SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
  SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
  SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
                           void(*)(void*), unsigned char encoding);
  SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
  SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
  SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
  SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
  
  /*
  ** CAPI3REF: Number Of SQL Parameters
  ** METHOD: sqlite3_stmt
  **
  ** ^This routine can be used to find the number of [SQL parameters]
  ** in a [prepared statement].  SQL parameters are tokens of the
  ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
  ** placeholders for values that are [sqlite3_bind_blob | bound]
  ** to the parameters at a later time.
  **
  ** ^(This routine actually returns the index of the largest (rightmost)
  ** parameter. For all forms except ?NNN, this will correspond to the
  ** number of unique parameters.  If parameters of the ?NNN form are used,
  ** there may be gaps in the list.)^
  **
  ** See also: [sqlite3_bind_blob|sqlite3_bind()],
  ** [sqlite3_bind_parameter_name()], and
  ** [sqlite3_bind_parameter_index()].
  */
  SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
  
  /*
  ** CAPI3REF: Name Of A Host Parameter
  ** METHOD: sqlite3_stmt
  **
  ** ^The sqlite3_bind_parameter_name(P,N) interface returns
  ** the name of the N-th [SQL parameter] in the [prepared statement] P.
  ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
  ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
  ** respectively.
  ** In other words, the initial ":" or "$" or "@" or "?"
  ** is included as part of the name.)^
  ** ^Parameters of the form "?" without a following integer have no name
  ** and are referred to as "nameless" or "anonymous parameters".
  **
  ** ^The first host parameter has an index of 1, not 0.
  **
  ** ^If the value N is out of range or if the N-th parameter is
  ** nameless, then NULL is returned.  ^The returned string is
  ** always in UTF-8 encoding even if the named parameter was
  ** originally specified as UTF-16 in [sqlite3_prepare16()],
  ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
  **
  ** See also: [sqlite3_bind_blob|sqlite3_bind()],
  ** [sqlite3_bind_parameter_count()], and
  ** [sqlite3_bind_parameter_index()].
  */
  SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
  
  /*
  ** CAPI3REF: Index Of A Parameter With A Given Name
  ** METHOD: sqlite3_stmt
  **
  ** ^Return the index of an SQL parameter given its name.  ^The
  ** index value returned is suitable for use as the second
  ** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
  ** is returned if no matching parameter is found.  ^The parameter
  ** name must be given in UTF-8 even if the original statement
  ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
  ** [sqlite3_prepare16_v3()].
  **
  ** See also: [sqlite3_bind_blob|sqlite3_bind()],
  ** [sqlite3_bind_parameter_count()], and
  ** [sqlite3_bind_parameter_name()].
  */
  SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
  
  /*
  ** CAPI3REF: Reset All Bindings On A Prepared Statement
  ** METHOD: sqlite3_stmt
  **
  ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
  ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
  ** ^Use this routine to reset all host parameters to NULL.
  */
  SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
  
  /*
  ** CAPI3REF: Number Of Columns In A Result Set
  ** METHOD: sqlite3_stmt
  **
  ** ^Return the number of columns in the result set returned by the
  ** [prepared statement]. ^If this routine returns 0, that means the
  ** [prepared statement] returns no data (for example an [UPDATE]).
  ** ^However, just because this routine returns a positive number does not
  ** mean that one or more rows of data will be returned.  ^A SELECT statement
  ** will always have a positive sqlite3_column_count() but depending on the
  ** WHERE clause constraints and the table content, it might return no rows.
  **
  ** See also: [sqlite3_data_count()]
  */
  SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
  
  /*
  ** CAPI3REF: Column Names In A Result Set
  ** METHOD: sqlite3_stmt
  **
  ** ^These routines return the name assigned to a particular column
  ** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
  ** interface returns a pointer to a zero-terminated UTF-8 string
  ** and sqlite3_column_name16() returns a pointer to a zero-terminated
  ** UTF-16 string.  ^The first parameter is the [prepared statement]
  ** that implements the [SELECT] statement. ^The second parameter is the
  ** column number.  ^The leftmost column is number 0.
  **
  ** ^The returned string pointer is valid until either the [prepared statement]
  ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
  ** reprepared by the first call to [sqlite3_step()] for a particular run
  ** or until the next call to
  ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
  **
  ** ^If sqlite3_malloc() fails during the processing of either routine
  ** (for example during a conversion from UTF-8 to UTF-16) then a
  ** NULL pointer is returned.
  **
  ** ^The name of a result column is the value of the "AS" clause for
  ** that column, if there is an AS clause.  If there is no AS clause
  ** then the name of the column is unspecified and may change from
  ** one release of SQLite to the next.
  */
  SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
  SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
  
  /*
  ** CAPI3REF: Source Of Data In A Query Result
  ** METHOD: sqlite3_stmt
  **
  ** ^These routines provide a means to determine the database, table, and
  ** table column that is the origin of a particular result column in
  ** [SELECT] statement.
  ** ^The name of the database or table or column can be returned as
  ** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
  ** the database name, the _table_ routines return the table name, and
  ** the origin_ routines return the column name.
  ** ^The returned string is valid until the [prepared statement] is destroyed
  ** using [sqlite3_finalize()] or until the statement is automatically
  ** reprepared by the first call to [sqlite3_step()] for a particular run
  ** or until the same information is requested
  ** again in a different encoding.
  **
  ** ^The names returned are the original un-aliased names of the
  ** database, table, and column.
  **
  ** ^The first argument to these interfaces is a [prepared statement].
  ** ^These functions return information about the Nth result column returned by
  ** the statement, where N is the second function argument.
  ** ^The left-most column is column 0 for these routines.
  **
  ** ^If the Nth column returned by the statement is an expression or
  ** subquery and is not a column value, then all of these functions return
  ** NULL.  ^These routines might also return NULL if a memory allocation error
  ** occurs.  ^Otherwise, they return the name of the attached database, table,
  ** or column that query result column was extracted from.
  **
  ** ^As with all other SQLite APIs, those whose names end with "16" return
  ** UTF-16 encoded strings and the other functions return UTF-8.
  **
  ** ^These APIs are only available if the library was compiled with the
  ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
  **
  ** If two or more threads call one or more
  ** [sqlite3_column_database_name | column metadata interfaces]
  ** for the same [prepared statement] and result column
  ** at the same time then the results are undefined.
  */
  SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
  SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
  SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
  SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
  SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
  SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
  
  /*
  ** CAPI3REF: Declared Datatype Of A Query Result
  ** METHOD: sqlite3_stmt
  **
  ** ^(The first parameter is a [prepared statement].
  ** If this statement is a [SELECT] statement and the Nth column of the
  ** returned result set of that [SELECT] is a table column (not an
  ** expression or subquery) then the declared type of the table
  ** column is returned.)^  ^If the Nth column of the result set is an
  ** expression or subquery, then a NULL pointer is returned.
  ** ^The returned string is always UTF-8 encoded.
  **
  ** ^(For example, given the database schema:
  **
  ** CREATE TABLE t1(c1 VARIANT);
  **
  ** and the following statement to be compiled:
  **
  ** SELECT c1 + 1, c1 FROM t1;
  **
  ** this routine would return the string "VARIANT" for the second result
  ** column (i==1), and a NULL pointer for the first result column (i==0).)^
  **
  ** ^SQLite uses dynamic run-time typing.  ^So just because a column
  ** is declared to contain a particular type does not mean that the
  ** data stored in that column is of the declared type.  SQLite is
  ** strongly typed, but the typing is dynamic not static.  ^Type
  ** is associated with individual values, not with the containers
  ** used to hold those values.
  */
  SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
  SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
  
  /*
  ** CAPI3REF: Evaluate An SQL Statement
  ** METHOD: sqlite3_stmt
  **
  ** After a [prepared statement] has been prepared using any of
  ** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
  ** or [sqlite3_prepare16_v3()] or one of the legacy
  ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
  ** must be called one or more times to evaluate the statement.
  **
  ** The details of the behavior of the sqlite3_step() interface depend
  ** on whether the statement was prepared using the newer "vX" interfaces
  ** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
  ** [sqlite3_prepare16_v2()] or the older legacy
  ** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
  ** new "vX" interface is recommended for new applications but the legacy
  ** interface will continue to be supported.
  **
  ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
  ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
  ** ^With the "v2" interface, any of the other [result codes] or
  ** [extended result codes] might be returned as well.
  **
  ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
  ** database locks it needs to do its job.  ^If the statement is a [COMMIT]
  ** or occurs outside of an explicit transaction, then you can retry the
  ** statement.  If the statement is not a [COMMIT] and occurs within an
  ** explicit transaction then you should rollback the transaction before
  ** continuing.
  **
  ** ^[SQLITE_DONE] means that the statement has finished executing
  ** successfully.  sqlite3_step() should not be called again on this virtual
  ** machine without first calling [sqlite3_reset()] to reset the virtual
  ** machine back to its initial state.
  **
  ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
  ** is returned each time a new row of data is ready for processing by the
  ** caller. The values may be accessed using the [column access functions].
  ** sqlite3_step() is called again to retrieve the next row of data.
  **
  ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
  ** violation) has occurred.  sqlite3_step() should not be called again on
  ** the VM. More information may be found by calling [sqlite3_errmsg()].
  ** ^With the legacy interface, a more specific error code (for example,
  ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
  ** can be obtained by calling [sqlite3_reset()] on the
  ** [prepared statement].  ^In the "v2" interface,
  ** the more specific error code is returned directly by sqlite3_step().
  **
  ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
  ** Perhaps it was called on a [prepared statement] that has
  ** already been [sqlite3_finalize | finalized] or on one that had
  ** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
  ** be the case that the same database connection is being used by two or
  ** more threads at the same moment in time.
  **
  ** For all versions of SQLite up to and including 3.6.23.1, a call to
  ** [sqlite3_reset()] was required after sqlite3_step() returned anything
  ** other than [SQLITE_ROW] before any subsequent invocation of
  ** sqlite3_step().  Failure to reset the prepared statement using
  ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
  ** sqlite3_step().  But after [version 3.6.23.1] ([dateof:3.6.23.1],
  ** sqlite3_step() began
  ** calling [sqlite3_reset()] automatically in this circumstance rather
  ** than returning [SQLITE_MISUSE].  This is not considered a compatibility
  ** break because any application that ever receives an SQLITE_MISUSE error
  ** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
  ** can be used to restore the legacy behavior.
  **
  ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
  ** API always returns a generic error code, [SQLITE_ERROR], following any
  ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
  ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
  ** specific [error codes] that better describes the error.
  ** We admit that this is a goofy design.  The problem has been fixed
  ** with the "v2" interface.  If you prepare all of your SQL statements
  ** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
  ** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
  ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
  ** then the more specific [error codes] are returned directly
  ** by sqlite3_step().  The use of the "vX" interfaces is recommended.
  */
  SQLITE_API int sqlite3_step(sqlite3_stmt*);
  
  /*
  ** CAPI3REF: Number of columns in a result set
  ** METHOD: sqlite3_stmt
  **
  ** ^The sqlite3_data_count(P) interface returns the number of columns in the
  ** current row of the result set of [prepared statement] P.
  ** ^If prepared statement P does not have results ready to return
  ** (via calls to the [sqlite3_column_int | sqlite3_column()] family of
  ** interfaces) then sqlite3_data_count(P) returns 0.
  ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
  ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
  ** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
  ** will return non-zero if previous call to [sqlite3_step](P) returned
  ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
  ** where it always returns zero since each step of that multi-step
  ** pragma returns 0 columns of data.
  **
  ** See also: [sqlite3_column_count()]
  */
  SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
  
  /*
  ** CAPI3REF: Fundamental Datatypes
  ** KEYWORDS: SQLITE_TEXT
  **
  ** ^(Every value in SQLite has one of five fundamental datatypes:
  **
  ** <ul>
  ** <li> 64-bit signed integer
  ** <li> 64-bit IEEE floating point number
  ** <li> string
  ** <li> BLOB
  ** <li> NULL
  ** </ul>)^
  **
  ** These constants are codes for each of those types.
  **
  ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
  ** for a completely different meaning.  Software that links against both
  ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
  ** SQLITE_TEXT.
  */
  #define SQLITE_INTEGER  1
  #define SQLITE_FLOAT    2
  #define SQLITE_BLOB     4
  #define SQLITE_NULL     5
  #ifdef SQLITE_TEXT
  # undef SQLITE_TEXT
  #else
  # define SQLITE_TEXT     3
  #endif
  #define SQLITE3_TEXT     3
  
  /*
  ** CAPI3REF: Result Values From A Query
  ** KEYWORDS: {column access functions}
  ** METHOD: sqlite3_stmt
  **
  ** <b>Summary:</b>
  ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
  ** <tr><td><b>sqlite3_column_blob</b><td>&rarr;<td>BLOB result
  ** <tr><td><b>sqlite3_column_double</b><td>&rarr;<td>REAL result
  ** <tr><td><b>sqlite3_column_int</b><td>&rarr;<td>32-bit INTEGER result
  ** <tr><td><b>sqlite3_column_int64</b><td>&rarr;<td>64-bit INTEGER result
  ** <tr><td><b>sqlite3_column_text</b><td>&rarr;<td>UTF-8 TEXT result
  ** <tr><td><b>sqlite3_column_text16</b><td>&rarr;<td>UTF-16 TEXT result
  ** <tr><td><b>sqlite3_column_value</b><td>&rarr;<td>The result as an
  ** [sqlite3_value|unprotected sqlite3_value] object.
  ** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
  ** <tr><td><b>sqlite3_column_bytes</b><td>&rarr;<td>Size of a BLOB
  ** or a UTF-8 TEXT result in bytes
  ** <tr><td><b>sqlite3_column_bytes16&nbsp;&nbsp;</b>
  ** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
  ** TEXT in bytes
  ** <tr><td><b>sqlite3_column_type</b><td>&rarr;<td>Default
  ** datatype of the result
  ** </table></blockquote>
  **
  ** <b>Details:</b>
  **
  ** ^These routines return information about a single column of the current
  ** result row of a query.  ^In every case the first argument is a pointer
  ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
  ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
  ** and the second argument is the index of the column for which information
  ** should be returned. ^The leftmost column of the result set has the index 0.
  ** ^The number of columns in the result can be determined using
  ** [sqlite3_column_count()].
  **
  ** If the SQL statement does not currently point to a valid row, or if the
  ** column index is out of range, the result is undefined.
  ** These routines may only be called when the most recent call to
  ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
  ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
  ** If any of these routines are called after [sqlite3_reset()] or
  ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
  ** something other than [SQLITE_ROW], the results are undefined.
  ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
  ** are called from a different thread while any of these routines
  ** are pending, then the results are undefined.
  **
  ** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
  ** each return the value of a result column in a specific data format.  If
  ** the result column is not initially in the requested format (for example,
  ** if the query returns an integer but the sqlite3_column_text() interface
  ** is used to extract the value) then an automatic type conversion is performed.
  **
  ** ^The sqlite3_column_type() routine returns the
  ** [SQLITE_INTEGER | datatype code] for the initial data type
  ** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
  ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
  ** The return value of sqlite3_column_type() can be used to decide which
  ** of the first six interface should be used to extract the column value.
  ** The value returned by sqlite3_column_type() is only meaningful if no
  ** automatic type conversions have occurred for the value in question.
  ** After a type conversion, the result of calling sqlite3_column_type()
  ** is undefined, though harmless.  Future
  ** versions of SQLite may change the behavior of sqlite3_column_type()
  ** following a type conversion.
  **
  ** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
  ** or sqlite3_column_bytes16() interfaces can be used to determine the size
  ** of that BLOB or string.
  **
  ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
  ** routine returns the number of bytes in that BLOB or string.
  ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
  ** the string to UTF-8 and then returns the number of bytes.
  ** ^If the result is a numeric value then sqlite3_column_bytes() uses
  ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
  ** the number of bytes in that string.
  ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
  **
  ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
  ** routine returns the number of bytes in that BLOB or string.
  ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
  ** the string to UTF-16 and then returns the number of bytes.
  ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
  ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
  ** the number of bytes in that string.
  ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
  **
  ** ^The values returned by [sqlite3_column_bytes()] and
  ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
  ** of the string.  ^For clarity: the values returned by
  ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
  ** bytes in the string, not the number of characters.
  **
  ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
  ** even empty strings, are always zero-terminated.  ^The return
  ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
  **
  ** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
  ** [unprotected sqlite3_value] object.  In a multithreaded environment,
  ** an unprotected sqlite3_value object may only be used safely with
  ** [sqlite3_bind_value()] and [sqlite3_result_value()].
  ** If the [unprotected sqlite3_value] object returned by
  ** [sqlite3_column_value()] is used in any other way, including calls
  ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
  ** or [sqlite3_value_bytes()], the behavior is not threadsafe.
  ** Hence, the sqlite3_column_value() interface
  ** is normally only useful within the implementation of
  ** [application-defined SQL functions] or [virtual tables], not within
  ** top-level application code.
  **
  ** The these routines may attempt to convert the datatype of the result.
  ** ^For example, if the internal representation is FLOAT and a text result
  ** is requested, [sqlite3_snprintf()] is used internally to perform the
  ** conversion automatically.  ^(The following table details the conversions
  ** that are applied:
  **
  ** <blockquote>
  ** <table border="1">
  ** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
  **
  ** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
  ** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
  ** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
  ** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
  ** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
  ** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
  ** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
  ** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
  ** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
  ** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
  ** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
  ** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
  ** <tr><td>  TEXT    <td>   BLOB    <td> No change
  ** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
  ** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
  ** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
  ** </table>
  ** </blockquote>)^
  **
  ** Note that when type conversions occur, pointers returned by prior
  ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
  ** sqlite3_column_text16() may be invalidated.
  ** Type conversions and pointer invalidations might occur
  ** in the following cases:
  **
  ** <ul>
  ** <li> The initial content is a BLOB and sqlite3_column_text() or
  **      sqlite3_column_text16() is called.  A zero-terminator might
  **      need to be added to the string.</li>
  ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
  **      sqlite3_column_text16() is called.  The content must be converted
  **      to UTF-16.</li>
  ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
  **      sqlite3_column_text() is called.  The content must be converted
  **      to UTF-8.</li>
  ** </ul>
  **
  ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
  ** not invalidate a prior pointer, though of course the content of the buffer
  ** that the prior pointer references will have been modified.  Other kinds
  ** of conversion are done in place when it is possible, but sometimes they
  ** are not possible and in those cases prior pointers are invalidated.
  **
  ** The safest policy is to invoke these routines
  ** in one of the following ways:
  **
  ** <ul>
  **  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
  **  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
  **  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
  ** </ul>
  **
  ** In other words, you should call sqlite3_column_text(),
  ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
  ** into the desired format, then invoke sqlite3_column_bytes() or
  ** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
  ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
  ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
  ** with calls to sqlite3_column_bytes().
  **
  ** ^The pointers returned are valid until a type conversion occurs as
  ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
  ** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
  ** and BLOBs is freed automatically.  Do not pass the pointers returned
  ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
  ** [sqlite3_free()].
  **
  ** As long as the input parameters are correct, these routines will only
  ** fail if an out-of-memory error occurs during a format conversion.
  ** Only the following subset of interfaces are subject to out-of-memory
  ** errors:
  **
  ** <ul>
  ** <li> sqlite3_column_blob()
  ** <li> sqlite3_column_text()
  ** <li> sqlite3_column_text16()
  ** <li> sqlite3_column_bytes()
  ** <li> sqlite3_column_bytes16()
  ** </ul>
  **
  ** If an out-of-memory error occurs, then the return value from these
  ** routines is the same as if the column had contained an SQL NULL value.
  ** Valid SQL NULL returns can be distinguished from out-of-memory errors
  ** by invoking the [sqlite3_errcode()] immediately after the suspect
  ** return value is obtained and before any
  ** other SQLite interface is called on the same [database connection].
  */
  SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
  SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
  SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
  SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
  SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
  SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
  SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
  SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
  SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
  SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
  
  /*
  ** CAPI3REF: Destroy A Prepared Statement Object
  ** DESTRUCTOR: sqlite3_stmt
  **
  ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
  ** ^If the most recent evaluation of the statement encountered no errors
  ** or if the statement is never been evaluated, then sqlite3_finalize() returns
  ** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
  ** sqlite3_finalize(S) returns the appropriate [error code] or
  ** [extended error code].
  **
  ** ^The sqlite3_finalize(S) routine can be called at any point during
  ** the life cycle of [prepared statement] S:
  ** before statement S is ever evaluated, after
  ** one or more calls to [sqlite3_reset()], or after any call
  ** to [sqlite3_step()] regardless of whether or not the statement has
  ** completed execution.
  **
  ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
  **
  ** The application must finalize every [prepared statement] in order to avoid
  ** resource leaks.  It is a grievous error for the application to try to use
  ** a prepared statement after it has been finalized.  Any use of a prepared
  ** statement after it has been finalized can result in undefined and
  ** undesirable behavior such as segfaults and heap corruption.
  */
  SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
  
  /*
  ** CAPI3REF: Reset A Prepared Statement Object
  ** METHOD: sqlite3_stmt
  **
  ** The sqlite3_reset() function is called to reset a [prepared statement]
  ** object back to its initial state, ready to be re-executed.
  ** ^Any SQL statement variables that had values bound to them using
  ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
  ** Use [sqlite3_clear_bindings()] to reset the bindings.
  **
  ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
  ** back to the beginning of its program.
  **
  ** ^If the most recent call to [sqlite3_step(S)] for the
  ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
  ** or if [sqlite3_step(S)] has never before been called on S,
  ** then [sqlite3_reset(S)] returns [SQLITE_OK].
  **
  ** ^If the most recent call to [sqlite3_step(S)] for the
  ** [prepared statement] S indicated an error, then
  ** [sqlite3_reset(S)] returns an appropriate [error code].
  **
  ** ^The [sqlite3_reset(S)] interface does not change the values
  ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
  */
  SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
  
  /*
  ** CAPI3REF: Create Or Redefine SQL Functions
  ** KEYWORDS: {function creation routines}
  ** METHOD: sqlite3
  **
  ** ^These functions (collectively known as "function creation routines")
  ** are used to add SQL functions or aggregates or to redefine the behavior
  ** of existing SQL functions or aggregates. The only differences between
  ** the three "sqlite3_create_function*" routines are the text encoding
  ** expected for the second parameter (the name of the function being
  ** created) and the presence or absence of a destructor callback for
  ** the application data pointer. Function sqlite3_create_window_function()
  ** is similar, but allows the user to supply the extra callback functions
  ** needed by [aggregate window functions].
  **
  ** ^The first parameter is the [database connection] to which the SQL
  ** function is to be added.  ^If an application uses more than one database
  ** connection then application-defined SQL functions must be added
  ** to each database connection separately.
  **
  ** ^The second parameter is the name of the SQL function to be created or
  ** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
  ** representation, exclusive of the zero-terminator.  ^Note that the name
  ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
  ** ^Any attempt to create a function with a longer name
  ** will result in [SQLITE_MISUSE] being returned.
  **
  ** ^The third parameter (nArg)
  ** is the number of arguments that the SQL function or
  ** aggregate takes. ^If this parameter is -1, then the SQL function or
  ** aggregate may take any number of arguments between 0 and the limit
  ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
  ** parameter is less than -1 or greater than 127 then the behavior is
  ** undefined.
  **
  ** ^The fourth parameter, eTextRep, specifies what
  ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
  ** its parameters.  The application should set this parameter to
  ** [SQLITE_UTF16LE] if the function implementation invokes
  ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
  ** implementation invokes [sqlite3_value_text16be()] on an input, or
  ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
  ** otherwise.  ^The same SQL function may be registered multiple times using
  ** different preferred text encodings, with different implementations for
  ** each encoding.
  ** ^When multiple implementations of the same function are available, SQLite
  ** will pick the one that involves the least amount of data conversion.
  **
  ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
  ** to signal that the function will always return the same result given
  ** the same inputs within a single SQL statement.  Most SQL functions are
  ** deterministic.  The built-in [random()] SQL function is an example of a
  ** function that is not deterministic.  The SQLite query planner is able to
  ** perform additional optimizations on deterministic functions, so use
  ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
  **
  ** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY]
  ** flag, which if present prevents the function from being invoked from
  ** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
  ** index expressions, or the WHERE clause of partial indexes.
  **
  ** <span style="background-color:#ffff90;">
  ** For best security, the [SQLITE_DIRECTONLY] flag is recommended for
  ** all application-defined SQL functions that do not need to be
  ** used inside of triggers, view, CHECK constraints, or other elements of
  ** the database schema.  This flags is especially recommended for SQL
  ** functions that have side effects or reveal internal application state.
  ** Without this flag, an attacker might be able to modify the schema of
  ** a database file to include invocations of the function with parameters
  ** chosen by the attacker, which the application will then execute when
  ** the database file is opened and read.
  ** </span>
  **
  ** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
  ** function can gain access to this pointer using [sqlite3_user_data()].)^
  **
  ** ^The sixth, seventh and eighth parameters passed to the three
  ** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
  ** pointers to C-language functions that implement the SQL function or
  ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
  ** callback only; NULL pointers must be passed as the xStep and xFinal
  ** parameters. ^An aggregate SQL function requires an implementation of xStep
  ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
  ** SQL function or aggregate, pass NULL pointers for all three function
  ** callbacks.
  **
  ** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
  ** and xInverse) passed to sqlite3_create_window_function are pointers to
  ** C-language callbacks that implement the new function. xStep and xFinal
  ** must both be non-NULL. xValue and xInverse may either both be NULL, in
  ** which case a regular aggregate function is created, or must both be
  ** non-NULL, in which case the new function may be used as either an aggregate
  ** or aggregate window function. More details regarding the implementation
  ** of aggregate window functions are
  ** [user-defined window functions|available here].
  **
  ** ^(If the final parameter to sqlite3_create_function_v2() or
  ** sqlite3_create_window_function() is not NULL, then it is destructor for
  ** the application data pointer. The destructor is invoked when the function
  ** is deleted, either by being overloaded or when the database connection
  ** closes.)^ ^The destructor is also invoked if the call to
  ** sqlite3_create_function_v2() fails.  ^When the destructor callback is
  ** invoked, it is passed a single argument which is a copy of the application
  ** data pointer which was the fifth parameter to sqlite3_create_function_v2().
  **
  ** ^It is permitted to register multiple implementations of the same
  ** functions with the same name but with either differing numbers of
  ** arguments or differing preferred text encodings.  ^SQLite will use
  ** the implementation that most closely matches the way in which the
  ** SQL function is used.  ^A function implementation with a non-negative
  ** nArg parameter is a better match than a function implementation with
  ** a negative nArg.  ^A function where the preferred text encoding
  ** matches the database encoding is a better
  ** match than a function where the encoding is different.
  ** ^A function where the encoding difference is between UTF16le and UTF16be
  ** is a closer match than a function where the encoding difference is
  ** between UTF8 and UTF16.
  **
  ** ^Built-in functions may be overloaded by new application-defined functions.
  **
  ** ^An application-defined function is permitted to call other
  ** SQLite interfaces.  However, such calls must not
  ** close the database connection nor finalize or reset the prepared
  ** statement in which the function is running.
  */
  SQLITE_API int sqlite3_create_function(
    sqlite3 *db,
    const char *zFunctionName,
    int nArg,
    int eTextRep,
    void *pApp,
    void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
    void (*xStep)(sqlite3_context*,int,sqlite3_value**),
    void (*xFinal)(sqlite3_context*)
  );
  SQLITE_API int sqlite3_create_function16(
    sqlite3 *db,
    const void *zFunctionName,
    int nArg,
    int eTextRep,
    void *pApp,
    void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
    void (*xStep)(sqlite3_context*,int,sqlite3_value**),
    void (*xFinal)(sqlite3_context*)
  );
  SQLITE_API int sqlite3_create_function_v2(
    sqlite3 *db,
    const char *zFunctionName,
    int nArg,
    int eTextRep,
    void *pApp,
    void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
    void (*xStep)(sqlite3_context*,int,sqlite3_value**),
    void (*xFinal)(sqlite3_context*),
    void(*xDestroy)(void*)
  );
  SQLITE_API int sqlite3_create_window_function(
    sqlite3 *db,
    const char *zFunctionName,
    int nArg,
    int eTextRep,
    void *pApp,
    void (*xStep)(sqlite3_context*,int,sqlite3_value**),
    void (*xFinal)(sqlite3_context*),
    void (*xValue)(sqlite3_context*),
    void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
    void(*xDestroy)(void*)
  );
  
  /*
  ** CAPI3REF: Text Encodings
  **
  ** These constant define integer codes that represent the various
  ** text encodings supported by SQLite.
  */
  #define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
  #define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
  #define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
  #define SQLITE_UTF16          4    /* Use native byte order */
  #define SQLITE_ANY            5    /* Deprecated */
  #define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
  
  /*
  ** CAPI3REF: Function Flags
  **
  ** These constants may be ORed together with the
  ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
  ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
  ** [sqlite3_create_function_v2()].
  **
  ** <dl>
  ** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd>
  ** The SQLITE_DETERMINISTIC flag means that the new function always gives
  ** the same output when the input parameters are the same.
  ** The [abs|abs() function] is deterministic, for example, but
  ** [randomblob|randomblob()] is not.  Functions must
  ** be deterministic in order to be used in certain contexts such as
  ** with the WHERE clause of [partial indexes] or in [generated columns].
  ** SQLite might also optimize deterministic functions by factoring them
  ** out of inner loops.
  ** </dd>
  **
  ** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd>
  ** The SQLITE_DIRECTONLY flag means that the function may only be invoked
  ** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
  ** schema structures such as [CHECK constraints], [DEFAULT clauses],
  ** [expression indexes], [partial indexes], or [generated columns].
  ** The SQLITE_DIRECTONLY flags is a security feature which is recommended
  ** for all [application-defined SQL functions], and especially for functions
  ** that have side-effects or that could potentially leak sensitive
  ** information.
  ** </dd>
  **
  ** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd>
  ** The SQLITE_INNOCUOUS flag means that the function is unlikely
  ** to cause problems even if misused.  An innocuous function should have
  ** no side effects and should not depend on any values other than its
  ** input parameters. The [abs|abs() function] is an example of an
  ** innocuous function.
  ** The [load_extension() SQL function] is not innocuous because of its
  ** side effects.
  ** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
  ** exactly the same.  The [random|random() function] is an example of a
  ** function that is innocuous but not deterministic.
  ** <p>Some heightened security settings
  ** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF])
  ** disable the use of SQL functions inside views and triggers and in
  ** schema structures such as [CHECK constraints], [DEFAULT clauses],
  ** [expression indexes], [partial indexes], and [generated columns] unless
  ** the function is tagged with SQLITE_INNOCUOUS.  Most built-in functions
  ** are innocuous.  Developers are advised to avoid using the
  ** SQLITE_INNOCUOUS flag for application-defined functions unless the
  ** function has been carefully audited and found to be free of potentially
  ** security-adverse side-effects and information-leaks.
  ** </dd>
  **
  ** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd>
  ** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call
  ** [sqlite3_value_subtype()] to inspect the sub-types of its arguments.
  ** Specifying this flag makes no difference for scalar or aggregate user
  ** functions. However, if it is not specified for a user-defined window
  ** function, then any sub-types belonging to arguments passed to the window
  ** function may be discarded before the window function is called (i.e.
  ** sqlite3_value_subtype() will always return 0).
  ** </dd>
  ** </dl>
  */
  #define SQLITE_DETERMINISTIC    0x000000800
  #define SQLITE_DIRECTONLY       0x000080000
  #define SQLITE_SUBTYPE          0x000100000
  #define SQLITE_INNOCUOUS        0x000200000
  
  /*
  ** CAPI3REF: Deprecated Functions
  ** DEPRECATED
  **
  ** These functions are [deprecated].  In order to maintain
  ** backwards compatibility with older code, these functions continue
  ** to be supported.  However, new applications should avoid
  ** the use of these functions.  To encourage programmers to avoid
  ** these functions, we will not explain what they do.
  */
  #ifndef SQLITE_OMIT_DEPRECATED
  SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
  SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
  SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
  SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
  SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
  SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
                        void*,sqlite3_int64);
  #endif
  
  /*
  ** CAPI3REF: Obtaining SQL Values
  ** METHOD: sqlite3_value
  **
  ** <b>Summary:</b>
  ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
  ** <tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
  ** <tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
  ** <tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
  ** <tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
  ** <tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
  ** <tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
  ** <tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
  ** the native byteorder
  ** <tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
  ** <tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
  ** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
  ** <tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
  ** or a UTF-8 TEXT in bytes
  ** <tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
  ** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
  ** TEXT in bytes
  ** <tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
  ** datatype of the value
  ** <tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
  ** <td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
  ** <tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
  ** <td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
  ** against a virtual table.
  ** <tr><td><b>sqlite3_value_frombind&nbsp;&nbsp;</b>
  ** <td>&rarr;&nbsp;&nbsp;<td>True if value originated from a [bound parameter]
  ** </table></blockquote>
  **
  ** <b>Details:</b>
  **
  ** These routines extract type, size, and content information from
  ** [protected sqlite3_value] objects.  Protected sqlite3_value objects
  ** are used to pass parameter information into the functions that
  ** implement [application-defined SQL functions] and [virtual tables].
  **
  ** These routines work only with [protected sqlite3_value] objects.
  ** Any attempt to use these routines on an [unprotected sqlite3_value]
  ** is not threadsafe.
  **
  ** ^These routines work just like the corresponding [column access functions]
  ** except that these routines take a single [protected sqlite3_value] object
  ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
  **
  ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
  ** in the native byte-order of the host machine.  ^The
  ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
  ** extract UTF-16 strings as big-endian and little-endian respectively.
  **
  ** ^If [sqlite3_value] object V was initialized
  ** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
  ** and if X and Y are strings that compare equal according to strcmp(X,Y),
  ** then sqlite3_value_pointer(V,Y) will return the pointer P.  ^Otherwise,
  ** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
  ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
  **
  ** ^(The sqlite3_value_type(V) interface returns the
  ** [SQLITE_INTEGER | datatype code] for the initial datatype of the
  ** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
  ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
  ** Other interfaces might change the datatype for an sqlite3_value object.
  ** For example, if the datatype is initially SQLITE_INTEGER and
  ** sqlite3_value_text(V) is called to extract a text value for that
  ** integer, then subsequent calls to sqlite3_value_type(V) might return
  ** SQLITE_TEXT.  Whether or not a persistent internal datatype conversion
  ** occurs is undefined and may change from one release of SQLite to the next.
  **
  ** ^(The sqlite3_value_numeric_type() interface attempts to apply
  ** numeric affinity to the value.  This means that an attempt is
  ** made to convert the value to an integer or floating point.  If
  ** such a conversion is possible without loss of information (in other
  ** words, if the value is a string that looks like a number)
  ** then the conversion is performed.  Otherwise no conversion occurs.
  ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
  **
  ** ^Within the [xUpdate] method of a [virtual table], the
  ** sqlite3_value_nochange(X) interface returns true if and only if
  ** the column corresponding to X is unchanged by the UPDATE operation
  ** that the xUpdate method call was invoked to implement and if
  ** and the prior [xColumn] method call that was invoked to extracted
  ** the value for that column returned without setting a result (probably
  ** because it queried [sqlite3_vtab_nochange()] and found that the column
  ** was unchanging).  ^Within an [xUpdate] method, any value for which
  ** sqlite3_value_nochange(X) is true will in all other respects appear
  ** to be a NULL value.  If sqlite3_value_nochange(X) is invoked anywhere other
  ** than within an [xUpdate] method call for an UPDATE statement, then
  ** the return value is arbitrary and meaningless.
  **
  ** ^The sqlite3_value_frombind(X) interface returns non-zero if the
  ** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
  ** interfaces.  ^If X comes from an SQL literal value, or a table column,
  ** or an expression, then sqlite3_value_frombind(X) returns zero.
  **
  ** Please pay particular attention to the fact that the pointer returned
  ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
  ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
  ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
  ** or [sqlite3_value_text16()].
  **
  ** These routines must be called from the same thread as
  ** the SQL function that supplied the [sqlite3_value*] parameters.
  **
  ** As long as the input parameter is correct, these routines can only
  ** fail if an out-of-memory error occurs during a format conversion.
  ** Only the following subset of interfaces are subject to out-of-memory
  ** errors:
  **
  ** <ul>
  ** <li> sqlite3_value_blob()
  ** <li> sqlite3_value_text()
  ** <li> sqlite3_value_text16()
  ** <li> sqlite3_value_text16le()
  ** <li> sqlite3_value_text16be()
  ** <li> sqlite3_value_bytes()
  ** <li> sqlite3_value_bytes16()
  ** </ul>
  **
  ** If an out-of-memory error occurs, then the return value from these
  ** routines is the same as if the column had contained an SQL NULL value.
  ** Valid SQL NULL returns can be distinguished from out-of-memory errors
  ** by invoking the [sqlite3_errcode()] immediately after the suspect
  ** return value is obtained and before any
  ** other SQLite interface is called on the same [database connection].
  */
  SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
  SQLITE_API double sqlite3_value_double(sqlite3_value*);
  SQLITE_API int sqlite3_value_int(sqlite3_value*);
  SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
  SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
  SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
  SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
  SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
  SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
  SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
  SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
  SQLITE_API int sqlite3_value_type(sqlite3_value*);
  SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
  SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
  SQLITE_API int sqlite3_value_frombind(sqlite3_value*);
  
  /*
  ** CAPI3REF: Finding The Subtype Of SQL Values
  ** METHOD: sqlite3_value
  **
  ** The sqlite3_value_subtype(V) function returns the subtype for
  ** an [application-defined SQL function] argument V.  The subtype
  ** information can be used to pass a limited amount of context from
  ** one SQL function to another.  Use the [sqlite3_result_subtype()]
  ** routine to set the subtype for the return value of an SQL function.
  */
  SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
  
  /*
  ** CAPI3REF: Copy And Free SQL Values
  ** METHOD: sqlite3_value
  **
  ** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
  ** object D and returns a pointer to that copy.  ^The [sqlite3_value] returned
  ** is a [protected sqlite3_value] object even if the input is not.
  ** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
  ** memory allocation fails.
  **
  ** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
  ** previously obtained from [sqlite3_value_dup()].  ^If V is a NULL pointer
  ** then sqlite3_value_free(V) is a harmless no-op.
  */
  SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
  SQLITE_API void sqlite3_value_free(sqlite3_value*);
  
  /*
  ** CAPI3REF: Obtain Aggregate Function Context
  ** METHOD: sqlite3_context
  **
  ** Implementations of aggregate SQL functions use this
  ** routine to allocate memory for storing their state.
  **
  ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
  ** for a particular aggregate function, SQLite allocates
  ** N bytes of memory, zeroes out that memory, and returns a pointer
  ** to the new memory. ^On second and subsequent calls to
  ** sqlite3_aggregate_context() for the same aggregate function instance,
  ** the same buffer is returned.  Sqlite3_aggregate_context() is normally
  ** called once for each invocation of the xStep callback and then one
  ** last time when the xFinal callback is invoked.  ^(When no rows match
  ** an aggregate query, the xStep() callback of the aggregate function
  ** implementation is never called and xFinal() is called exactly once.
  ** In those cases, sqlite3_aggregate_context() might be called for the
  ** first time from within xFinal().)^
  **
  ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
  ** when first called if N is less than or equal to zero or if a memory
  ** allocate error occurs.
  **
  ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
  ** determined by the N parameter on first successful call.  Changing the
  ** value of N in any subsequent call to sqlite3_aggregate_context() within
  ** the same aggregate function instance will not resize the memory
  ** allocation.)^  Within the xFinal callback, it is customary to set
  ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
  ** pointless memory allocations occur.
  **
  ** ^SQLite automatically frees the memory allocated by
  ** sqlite3_aggregate_context() when the aggregate query concludes.
  **
  ** The first parameter must be a copy of the
  ** [sqlite3_context | SQL function context] that is the first parameter
  ** to the xStep or xFinal callback routine that implements the aggregate
  ** function.
  **
  ** This routine must be called from the same thread in which
  ** the aggregate SQL function is running.
  */
  SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
  
  /*
  ** CAPI3REF: User Data For Functions
  ** METHOD: sqlite3_context
  **
  ** ^The sqlite3_user_data() interface returns a copy of
  ** the pointer that was the pUserData parameter (the 5th parameter)
  ** of the [sqlite3_create_function()]
  ** and [sqlite3_create_function16()] routines that originally
  ** registered the application defined function.
  **
  ** This routine must be called from the same thread in which
  ** the application-defined function is running.
  */
  SQLITE_API void *sqlite3_user_data(sqlite3_context*);
  
  /*
  ** CAPI3REF: Database Connection For Functions
  ** METHOD: sqlite3_context
  **
  ** ^The sqlite3_context_db_handle() interface returns a copy of
  ** the pointer to the [database connection] (the 1st parameter)
  ** of the [sqlite3_create_function()]
  ** and [sqlite3_create_function16()] routines that originally
  ** registered the application defined function.
  */
  SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
  
  /*
  ** CAPI3REF: Function Auxiliary Data
  ** METHOD: sqlite3_context
  **
  ** These functions may be used by (non-aggregate) SQL functions to
  ** associate metadata with argument values. If the same value is passed to
  ** multiple invocations of the same SQL function during query execution, under
  ** some circumstances the associated metadata may be preserved.  An example
  ** of where this might be useful is in a regular-expression matching
  ** function. The compiled version of the regular expression can be stored as
  ** metadata associated with the pattern string.
  ** Then as long as the pattern string remains the same,
  ** the compiled regular expression can be reused on multiple
  ** invocations of the same function.
  **
  ** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
  ** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
  ** value to the application-defined function.  ^N is zero for the left-most
  ** function argument.  ^If there is no metadata
  ** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
  ** returns a NULL pointer.
  **
  ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
  ** argument of the application-defined function.  ^Subsequent
  ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
  ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
  ** NULL if the metadata has been discarded.
  ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
  ** SQLite will invoke the destructor function X with parameter P exactly
  ** once, when the metadata is discarded.
  ** SQLite is free to discard the metadata at any time, including: <ul>
  ** <li> ^(when the corresponding function parameter changes)^, or
  ** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
  **      SQL statement)^, or
  ** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
  **       parameter)^, or
  ** <li> ^(during the original sqlite3_set_auxdata() call when a memory
  **      allocation error occurs.)^ </ul>
  **
  ** Note the last bullet in particular.  The destructor X in
  ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
  ** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
  ** should be called near the end of the function implementation and the
  ** function implementation should not make any use of P after
  ** sqlite3_set_auxdata() has been called.
  **
  ** ^(In practice, metadata is preserved between function calls for
  ** function parameters that are compile-time constants, including literal
  ** values and [parameters] and expressions composed from the same.)^
  **
  ** The value of the N parameter to these interfaces should be non-negative.
  ** Future enhancements may make use of negative N values to define new
  ** kinds of function caching behavior.
  **
  ** These routines must be called from the same thread in which
  ** the SQL function is running.
  */
  SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
  SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
  
  
  /*
  ** CAPI3REF: Constants Defining Special Destructor Behavior
  **
  ** These are special values for the destructor that is passed in as the
  ** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
  ** argument is SQLITE_STATIC, it means that the content pointer is constant
  ** and will never change.  It does not need to be destroyed.  ^The
  ** SQLITE_TRANSIENT value means that the content will likely change in
  ** the near future and that SQLite should make its own private copy of
  ** the content before returning.
  **
  ** The typedef is necessary to work around problems in certain
  ** C++ compilers.
  */
  typedef void (*sqlite3_destructor_type)(void*);
  #define SQLITE_STATIC      ((sqlite3_destructor_type)0)
  #define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
  
  /*
  ** CAPI3REF: Setting The Result Of An SQL Function
  ** METHOD: sqlite3_context
  **
  ** These routines are used by the xFunc or xFinal callbacks that
  ** implement SQL functions and aggregates.  See
  ** [sqlite3_create_function()] and [sqlite3_create_function16()]
  ** for additional information.
  **
  ** These functions work very much like the [parameter binding] family of
  ** functions used to bind values to host parameters in prepared statements.
  ** Refer to the [SQL parameter] documentation for additional information.
  **
  ** ^The sqlite3_result_blob() interface sets the result from
  ** an application-defined function to be the BLOB whose content is pointed
  ** to by the second parameter and which is N bytes long where N is the
  ** third parameter.
  **
  ** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
  ** interfaces set the result of the application-defined function to be
  ** a BLOB containing all zero bytes and N bytes in size.
  **
  ** ^The sqlite3_result_double() interface sets the result from
  ** an application-defined function to be a floating point value specified
  ** by its 2nd argument.
  **
  ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
  ** cause the implemented SQL function to throw an exception.
  ** ^SQLite uses the string pointed to by the
  ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
  ** as the text of an error message.  ^SQLite interprets the error
  ** message string from sqlite3_result_error() as UTF-8. ^SQLite
  ** interprets the string from sqlite3_result_error16() as UTF-16 using
  ** the same [byte-order determination rules] as [sqlite3_bind_text16()].
  ** ^If the third parameter to sqlite3_result_error()
  ** or sqlite3_result_error16() is negative then SQLite takes as the error
  ** message all text up through the first zero character.
  ** ^If the third parameter to sqlite3_result_error() or
  ** sqlite3_result_error16() is non-negative then SQLite takes that many
  ** bytes (not characters) from the 2nd parameter as the error message.
  ** ^The sqlite3_result_error() and sqlite3_result_error16()
  ** routines make a private copy of the error message text before
  ** they return.  Hence, the calling function can deallocate or
  ** modify the text after they return without harm.
  ** ^The sqlite3_result_error_code() function changes the error code
  ** returned by SQLite as a result of an error in a function.  ^By default,
  ** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
  ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
  **
  ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
  ** error indicating that a string or BLOB is too long to represent.
  **
  ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
  ** error indicating that a memory allocation failed.
  **
  ** ^The sqlite3_result_int() interface sets the return value
  ** of the application-defined function to be the 32-bit signed integer
  ** value given in the 2nd argument.
  ** ^The sqlite3_result_int64() interface sets the return value
  ** of the application-defined function to be the 64-bit signed integer
  ** value given in the 2nd argument.
  **
  ** ^The sqlite3_result_null() interface sets the return value
  ** of the application-defined function to be NULL.
  **
  ** ^The sqlite3_result_text(), sqlite3_result_text16(),
  ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
  ** set the return value of the application-defined function to be
  ** a text string which is represented as UTF-8, UTF-16 native byte order,
  ** UTF-16 little endian, or UTF-16 big endian, respectively.
  ** ^The sqlite3_result_text64() interface sets the return value of an
  ** application-defined function to be a text string in an encoding
  ** specified by the fifth (and last) parameter, which must be one
  ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
  ** ^SQLite takes the text result from the application from
  ** the 2nd parameter of the sqlite3_result_text* interfaces.
  ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
  ** is negative, then SQLite takes result text from the 2nd parameter
  ** through the first zero character.
  ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
  ** is non-negative, then as many bytes (not characters) of the text
  ** pointed to by the 2nd parameter are taken as the application-defined
  ** function result.  If the 3rd parameter is non-negative, then it
  ** must be the byte offset into the string where the NUL terminator would
  ** appear if the string where NUL terminated.  If any NUL characters occur
  ** in the string at a byte offset that is less than the value of the 3rd
  ** parameter, then the resulting string will contain embedded NULs and the
  ** result of expressions operating on strings with embedded NULs is undefined.
  ** ^If the 4th parameter to the sqlite3_result_text* interfaces
  ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
  ** function as the destructor on the text or BLOB result when it has
  ** finished using that result.
  ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
  ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
  ** assumes that the text or BLOB result is in constant space and does not
  ** copy the content of the parameter nor call a destructor on the content
  ** when it has finished using that result.
  ** ^If the 4th parameter to the sqlite3_result_text* interfaces
  ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
  ** then SQLite makes a copy of the result into space obtained
  ** from [sqlite3_malloc()] before it returns.
  **
  ** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and
  ** sqlite3_result_text16be() routines, and for sqlite3_result_text64()
  ** when the encoding is not UTF8, if the input UTF16 begins with a
  ** byte-order mark (BOM, U+FEFF) then the BOM is removed from the
  ** string and the rest of the string is interpreted according to the
  ** byte-order specified by the BOM.  ^The byte-order specified by
  ** the BOM at the beginning of the text overrides the byte-order
  ** specified by the interface procedure.  ^So, for example, if
  ** sqlite3_result_text16le() is invoked with text that begins
  ** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
  ** first two bytes of input are skipped and the remaining input
  ** is interpreted as UTF16BE text.
  **
  ** ^For UTF16 input text to the sqlite3_result_text16(),
  ** sqlite3_result_text16be(), sqlite3_result_text16le(), and
  ** sqlite3_result_text64() routines, if the text contains invalid
  ** UTF16 characters, the invalid characters might be converted
  ** into the unicode replacement character, U+FFFD.
  **
  ** ^The sqlite3_result_value() interface sets the result of
  ** the application-defined function to be a copy of the
  ** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
  ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
  ** so that the [sqlite3_value] specified in the parameter may change or
  ** be deallocated after sqlite3_result_value() returns without harm.
  ** ^A [protected sqlite3_value] object may always be used where an
  ** [unprotected sqlite3_value] object is required, so either
  ** kind of [sqlite3_value] object can be used with this interface.
  **
  ** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
  ** SQL NULL value, just like [sqlite3_result_null(C)], except that it
  ** also associates the host-language pointer P or type T with that
  ** NULL value such that the pointer can be retrieved within an
  ** [application-defined SQL function] using [sqlite3_value_pointer()].
  ** ^If the D parameter is not NULL, then it is a pointer to a destructor
  ** for the P parameter.  ^SQLite invokes D with P as its only argument
  ** when SQLite is finished with P.  The T parameter should be a static
  ** string and preferably a string literal. The sqlite3_result_pointer()
  ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
  **
  ** If these routines are called from within the different thread
  ** than the one containing the application-defined function that received
  ** the [sqlite3_context] pointer, the results are undefined.
  */
  SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
  SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
                             sqlite3_uint64,void(*)(void*));
  SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
  SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
  SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
  SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
  SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
  SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
  SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
  SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
  SQLITE_API void sqlite3_result_null(sqlite3_context*);
  SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
  SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
                             void(*)(void*), unsigned char encoding);
  SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
  SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
  SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
  SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
  SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
  SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
  SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
  
  
  /*
  ** CAPI3REF: Setting The Subtype Of An SQL Function
  ** METHOD: sqlite3_context
  **
  ** The sqlite3_result_subtype(C,T) function causes the subtype of
  ** the result from the [application-defined SQL function] with
  ** [sqlite3_context] C to be the value T.  Only the lower 8 bits
  ** of the subtype T are preserved in current versions of SQLite;
  ** higher order bits are discarded.
  ** The number of subtype bytes preserved by SQLite might increase
  ** in future releases of SQLite.
  */
  SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
  
  /*
  ** CAPI3REF: Define New Collating Sequences
  ** METHOD: sqlite3
  **
  ** ^These functions add, remove, or modify a [collation] associated
  ** with the [database connection] specified as the first argument.
  **
  ** ^The name of the collation is a UTF-8 string
  ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
  ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
  ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
  ** considered to be the same name.
  **
  ** ^(The third argument (eTextRep) must be one of the constants:
  ** <ul>
  ** <li> [SQLITE_UTF8],
  ** <li> [SQLITE_UTF16LE],
  ** <li> [SQLITE_UTF16BE],
  ** <li> [SQLITE_UTF16], or
  ** <li> [SQLITE_UTF16_ALIGNED].
  ** </ul>)^
  ** ^The eTextRep argument determines the encoding of strings passed
  ** to the collating function callback, xCompare.
  ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
  ** force strings to be UTF16 with native byte order.
  ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
  ** on an even byte address.
  **
  ** ^The fourth argument, pArg, is an application data pointer that is passed
  ** through as the first argument to the collating function callback.
  **
  ** ^The fifth argument, xCompare, is a pointer to the collating function.
  ** ^Multiple collating functions can be registered using the same name but
  ** with different eTextRep parameters and SQLite will use whichever
  ** function requires the least amount of data transformation.
  ** ^If the xCompare argument is NULL then the collating function is
  ** deleted.  ^When all collating functions having the same name are deleted,
  ** that collation is no longer usable.
  **
  ** ^The collating function callback is invoked with a copy of the pArg
  ** application data pointer and with two strings in the encoding specified
  ** by the eTextRep argument.  The two integer parameters to the collating
  ** function callback are the length of the two strings, in bytes. The collating
  ** function must return an integer that is negative, zero, or positive
  ** if the first string is less than, equal to, or greater than the second,
  ** respectively.  A collating function must always return the same answer
  ** given the same inputs.  If two or more collating functions are registered
  ** to the same collation name (using different eTextRep values) then all
  ** must give an equivalent answer when invoked with equivalent strings.
  ** The collating function must obey the following properties for all
  ** strings A, B, and C:
  **
  ** <ol>
  ** <li> If A==B then B==A.
  ** <li> If A==B and B==C then A==C.
  ** <li> If A&lt;B THEN B&gt;A.
  ** <li> If A&lt;B and B&lt;C then A&lt;C.
  ** </ol>
  **
  ** If a collating function fails any of the above constraints and that
  ** collating function is registered and used, then the behavior of SQLite
  ** is undefined.
  **
  ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
  ** with the addition that the xDestroy callback is invoked on pArg when
  ** the collating function is deleted.
  ** ^Collating functions are deleted when they are overridden by later
  ** calls to the collation creation functions or when the
  ** [database connection] is closed using [sqlite3_close()].
  **
  ** ^The xDestroy callback is <u>not</u> called if the
  ** sqlite3_create_collation_v2() function fails.  Applications that invoke
  ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
  ** check the return code and dispose of the application data pointer
  ** themselves rather than expecting SQLite to deal with it for them.
  ** This is different from every other SQLite interface.  The inconsistency
  ** is unfortunate but cannot be changed without breaking backwards
  ** compatibility.
  **
  ** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
  */
  SQLITE_API int sqlite3_create_collation(
    sqlite3*,
    const char *zName,
    int eTextRep,
    void *pArg,
    int(*xCompare)(void*,int,const void*,int,const void*)
  );
  SQLITE_API int sqlite3_create_collation_v2(
    sqlite3*,
    const char *zName,
    int eTextRep,
    void *pArg,
    int(*xCompare)(void*,int,const void*,int,const void*),
    void(*xDestroy)(void*)
  );
  SQLITE_API int sqlite3_create_collation16(
    sqlite3*,
    const void *zName,
    int eTextRep,
    void *pArg,
    int(*xCompare)(void*,int,const void*,int,const void*)
  );
  
  /*
  ** CAPI3REF: Collation Needed Callbacks
  ** METHOD: sqlite3
  **
  ** ^To avoid having to register all collation sequences before a database
  ** can be used, a single callback function may be registered with the
  ** [database connection] to be invoked whenever an undefined collation
  ** sequence is required.
  **
  ** ^If the function is registered using the sqlite3_collation_needed() API,
  ** then it is passed the names of undefined collation sequences as strings
  ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
  ** the names are passed as UTF-16 in machine native byte order.
  ** ^A call to either function replaces the existing collation-needed callback.
  **
  ** ^(When the callback is invoked, the first argument passed is a copy
  ** of the second argument to sqlite3_collation_needed() or
  ** sqlite3_collation_needed16().  The second argument is the database
  ** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
  ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
  ** sequence function required.  The fourth parameter is the name of the
  ** required collation sequence.)^
  **
  ** The callback function should register the desired collation using
  ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
  ** [sqlite3_create_collation_v2()].
  */
  SQLITE_API int sqlite3_collation_needed(
    sqlite3*,
    void*,
    void(*)(void*,sqlite3*,int eTextRep,const char*)
  );
  SQLITE_API int sqlite3_collation_needed16(
    sqlite3*,
    void*,
    void(*)(void*,sqlite3*,int eTextRep,const void*)
  );
  
  #ifdef SQLITE_ENABLE_CEROD
  /*
  ** Specify the activation key for a CEROD database.  Unless
  ** activated, none of the CEROD routines will work.
  */
  SQLITE_API void sqlite3_activate_cerod(
    const char *zPassPhrase        /* Activation phrase */
  );
  #endif
  
  /*
  ** CAPI3REF: Suspend Execution For A Short Time
  **
  ** The sqlite3_sleep() function causes the current thread to suspend execution
  ** for at least a number of milliseconds specified in its parameter.
  **
  ** If the operating system does not support sleep requests with
  ** millisecond time resolution, then the time will be rounded up to
  ** the nearest second. The number of milliseconds of sleep actually
  ** requested from the operating system is returned.
  **
  ** ^SQLite implements this interface by calling the xSleep()
  ** method of the default [sqlite3_vfs] object.  If the xSleep() method
  ** of the default VFS is not implemented correctly, or not implemented at
  ** all, then the behavior of sqlite3_sleep() may deviate from the description
  ** in the previous paragraphs.
  */
  SQLITE_API int sqlite3_sleep(int);
  
  /*
  ** CAPI3REF: Name Of The Folder Holding Temporary Files
  **
  ** ^(If this global variable is made to point to a string which is
  ** the name of a folder (a.k.a. directory), then all temporary files
  ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
  ** will be placed in that directory.)^  ^If this variable
  ** is a NULL pointer, then SQLite performs a search for an appropriate
  ** temporary file directory.
  **
  ** Applications are strongly discouraged from using this global variable.
  ** It is required to set a temporary folder on Windows Runtime (WinRT).
  ** But for all other platforms, it is highly recommended that applications
  ** neither read nor write this variable.  This global variable is a relic
  ** that exists for backwards compatibility of legacy applications and should
  ** be avoided in new projects.
  **
  ** It is not safe to read or modify this variable in more than one
  ** thread at a time.  It is not safe to read or modify this variable
  ** if a [database connection] is being used at the same time in a separate
  ** thread.
  ** It is intended that this variable be set once
  ** as part of process initialization and before any SQLite interface
  ** routines have been called and that this variable remain unchanged
  ** thereafter.
  **
  ** ^The [temp_store_directory pragma] may modify this variable and cause
  ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
  ** the [temp_store_directory pragma] always assumes that any string
  ** that this variable points to is held in memory obtained from
  ** [sqlite3_malloc] and the pragma may attempt to free that memory
  ** using [sqlite3_free].
  ** Hence, if this variable is modified directly, either it should be
  ** made NULL or made to point to memory obtained from [sqlite3_malloc]
  ** or else the use of the [temp_store_directory pragma] should be avoided.
  ** Except when requested by the [temp_store_directory pragma], SQLite
  ** does not free the memory that sqlite3_temp_directory points to.  If
  ** the application wants that memory to be freed, it must do
  ** so itself, taking care to only do so after all [database connection]
  ** objects have been destroyed.
  **
  ** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
  ** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
  ** features that require the use of temporary files may fail.  Here is an
  ** example of how to do this using C++ with the Windows Runtime:
  **
  ** <blockquote><pre>
  ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
  ** &nbsp;     TemporaryFolder->Path->Data();
  ** char zPathBuf&#91;MAX_PATH + 1&#93;;
  ** memset(zPathBuf, 0, sizeof(zPathBuf));
  ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
  ** &nbsp;     NULL, NULL);
  ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
  ** </pre></blockquote>
  */
  SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
  
  /*
  ** CAPI3REF: Name Of The Folder Holding Database Files
  **
  ** ^(If this global variable is made to point to a string which is
  ** the name of a folder (a.k.a. directory), then all database files
  ** specified with a relative pathname and created or accessed by
  ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
  ** to be relative to that directory.)^ ^If this variable is a NULL
  ** pointer, then SQLite assumes that all database files specified
  ** with a relative pathname are relative to the current directory
  ** for the process.  Only the windows VFS makes use of this global
  ** variable; it is ignored by the unix VFS.
  **
  ** Changing the value of this variable while a database connection is
  ** open can result in a corrupt database.
  **
  ** It is not safe to read or modify this variable in more than one
  ** thread at a time.  It is not safe to read or modify this variable
  ** if a [database connection] is being used at the same time in a separate
  ** thread.
  ** It is intended that this variable be set once
  ** as part of process initialization and before any SQLite interface
  ** routines have been called and that this variable remain unchanged
  ** thereafter.
  **
  ** ^The [data_store_directory pragma] may modify this variable and cause
  ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
  ** the [data_store_directory pragma] always assumes that any string
  ** that this variable points to is held in memory obtained from
  ** [sqlite3_malloc] and the pragma may attempt to free that memory
  ** using [sqlite3_free].
  ** Hence, if this variable is modified directly, either it should be
  ** made NULL or made to point to memory obtained from [sqlite3_malloc]
  ** or else the use of the [data_store_directory pragma] should be avoided.
  */
  SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
  
  /*
  ** CAPI3REF: Win32 Specific Interface
  **
  ** These interfaces are available only on Windows.  The
  ** [sqlite3_win32_set_directory] interface is used to set the value associated
  ** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
  ** zValue, depending on the value of the type parameter.  The zValue parameter
  ** should be NULL to cause the previous value to be freed via [sqlite3_free];
  ** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
  ** prior to being used.  The [sqlite3_win32_set_directory] interface returns
  ** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
  ** or [SQLITE_NOMEM] if memory could not be allocated.  The value of the
  ** [sqlite3_data_directory] variable is intended to act as a replacement for
  ** the current directory on the sub-platforms of Win32 where that concept is
  ** not present, e.g. WinRT and UWP.  The [sqlite3_win32_set_directory8] and
  ** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
  ** sqlite3_win32_set_directory interface except the string parameter must be
  ** UTF-8 or UTF-16, respectively.
  */
  SQLITE_API int sqlite3_win32_set_directory(
    unsigned long type, /* Identifier for directory being set or reset */
    void *zValue        /* New value for directory being set or reset */
  );
  SQLITE_API int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
  SQLITE_API int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
  
  /*
  ** CAPI3REF: Win32 Directory Types
  **
  ** These macros are only available on Windows.  They define the allowed values
  ** for the type argument to the [sqlite3_win32_set_directory] interface.
  */
  #define SQLITE_WIN32_DATA_DIRECTORY_TYPE  1
  #define SQLITE_WIN32_TEMP_DIRECTORY_TYPE  2
  
  /*
  ** CAPI3REF: Test For Auto-Commit Mode
  ** KEYWORDS: {autocommit mode}
  ** METHOD: sqlite3
  **
  ** ^The sqlite3_get_autocommit() interface returns non-zero or
  ** zero if the given database connection is or is not in autocommit mode,
  ** respectively.  ^Autocommit mode is on by default.
  ** ^Autocommit mode is disabled by a [BEGIN] statement.
  ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
  **
  ** If certain kinds of errors occur on a statement within a multi-statement
  ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
  ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
  ** transaction might be rolled back automatically.  The only way to
  ** find out whether SQLite automatically rolled back the transaction after
  ** an error is to use this function.
  **
  ** If another thread changes the autocommit status of the database
  ** connection while this routine is running, then the return value
  ** is undefined.
  */
  SQLITE_API int sqlite3_get_autocommit(sqlite3*);
  
  /*
  ** CAPI3REF: Find The Database Handle Of A Prepared Statement
  ** METHOD: sqlite3_stmt
  **
  ** ^The sqlite3_db_handle interface returns the [database connection] handle
  ** to which a [prepared statement] belongs.  ^The [database connection]
  ** returned by sqlite3_db_handle is the same [database connection]
  ** that was the first argument
  ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
  ** create the statement in the first place.
  */
  SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
  
  /*
  ** CAPI3REF: Return The Filename For A Database Connection
  ** METHOD: sqlite3
  **
  ** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename
  ** associated with database N of connection D.
  ** ^If there is no attached database N on the database
  ** connection D, or if database N is a temporary or in-memory database, then
  ** this function will return either a NULL pointer or an empty string.
  **
  ** ^The string value returned by this routine is owned and managed by
  ** the database connection.  ^The value will be valid until the database N
  ** is [DETACH]-ed or until the database connection closes.
  **
  ** ^The filename returned by this function is the output of the
  ** xFullPathname method of the [VFS].  ^In other words, the filename
  ** will be an absolute pathname, even if the filename used
  ** to open the database originally was a URI or relative pathname.
  **
  ** If the filename pointer returned by this routine is not NULL, then it
  ** can be used as the filename input parameter to these routines:
  ** <ul>
  ** <li> [sqlite3_uri_parameter()]
  ** <li> [sqlite3_uri_boolean()]
  ** <li> [sqlite3_uri_int64()]
  ** <li> [sqlite3_filename_database()]
  ** <li> [sqlite3_filename_journal()]
  ** <li> [sqlite3_filename_wal()]
  ** </ul>
  */
  SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
  
  /*
  ** CAPI3REF: Determine if a database is read-only
  ** METHOD: sqlite3
  **
  ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
  ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
  ** the name of a database on connection D.
  */
  SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
  
  /*
  ** CAPI3REF: Determine the transaction state of a database
  ** METHOD: sqlite3
  **
  ** ^The sqlite3_txn_state(D,S) interface returns the current
  ** [transaction state] of schema S in database connection D.  ^If S is NULL,
  ** then the highest transaction state of any schema on database connection D
  ** is returned.  Transaction states are (in order of lowest to highest):
  ** <ol>
  ** <li value="0"> SQLITE_TXN_NONE
  ** <li value="1"> SQLITE_TXN_READ
  ** <li value="2"> SQLITE_TXN_WRITE
  ** </ol>
  ** ^If the S argument to sqlite3_txn_state(D,S) is not the name of
  ** a valid schema, then -1 is returned.
  */
  SQLITE_API int sqlite3_txn_state(sqlite3*,const char *zSchema);
  
  /*
  ** CAPI3REF: Allowed return values from [sqlite3_txn_state()]
  ** KEYWORDS: {transaction state}
  **
  ** These constants define the current transaction state of a database file.
  ** ^The [sqlite3_txn_state(D,S)] interface returns one of these
  ** constants in order to describe the transaction state of schema S
  ** in [database connection] D.
  **
  ** <dl>
  ** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt>
  ** <dd>The SQLITE_TXN_NONE state means that no transaction is currently
  ** pending.</dd>
  **
  ** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt>
  ** <dd>The SQLITE_TXN_READ state means that the database is currently
  ** in a read transaction.  Content has been read from the database file
  ** but nothing in the database file has changed.  The transaction state
  ** will advanced to SQLITE_TXN_WRITE if any changes occur and there are
  ** no other conflicting concurrent write transactions.  The transaction
  ** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or
  ** [COMMIT].</dd>
  **
  ** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt>
  ** <dd>The SQLITE_TXN_WRITE state means that the database is currently
  ** in a write transaction.  Content has been written to the database file
  ** but has not yet committed.  The transaction state will change to
  ** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd>
  */
  #define SQLITE_TXN_NONE  0
  #define SQLITE_TXN_READ  1
  #define SQLITE_TXN_WRITE 2
  
  /*
  ** CAPI3REF: Find the next prepared statement
  ** METHOD: sqlite3
  **
  ** ^This interface returns a pointer to the next [prepared statement] after
  ** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
  ** then this interface returns a pointer to the first prepared statement
  ** associated with the database connection pDb.  ^If no prepared statement
  ** satisfies the conditions of this routine, it returns NULL.
  **
  ** The [database connection] pointer D in a call to
  ** [sqlite3_next_stmt(D,S)] must refer to an open database
  ** connection and in particular must not be a NULL pointer.
  */
  SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
  
  /*
  ** CAPI3REF: Commit And Rollback Notification Callbacks
  ** METHOD: sqlite3
  **
  ** ^The sqlite3_commit_hook() interface registers a callback
  ** function to be invoked whenever a transaction is [COMMIT | committed].
  ** ^Any callback set by a previous call to sqlite3_commit_hook()
  ** for the same database connection is overridden.
  ** ^The sqlite3_rollback_hook() interface registers a callback
  ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
  ** ^Any callback set by a previous call to sqlite3_rollback_hook()
  ** for the same database connection is overridden.
  ** ^The pArg argument is passed through to the callback.
  ** ^If the callback on a commit hook function returns non-zero,
  ** then the commit is converted into a rollback.
  **
  ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
  ** return the P argument from the previous call of the same function
  ** on the same [database connection] D, or NULL for
  ** the first call for each function on D.
  **
  ** The commit and rollback hook callbacks are not reentrant.
  ** The callback implementation must not do anything that will modify
  ** the database connection that invoked the callback.  Any actions
  ** to modify the database connection must be deferred until after the
  ** completion of the [sqlite3_step()] call that triggered the commit
  ** or rollback hook in the first place.
  ** Note that running any other SQL statements, including SELECT statements,
  ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
  ** the database connections for the meaning of "modify" in this paragraph.
  **
  ** ^Registering a NULL function disables the callback.
  **
  ** ^When the commit hook callback routine returns zero, the [COMMIT]
  ** operation is allowed to continue normally.  ^If the commit hook
  ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
  ** ^The rollback hook is invoked on a rollback that results from a commit
  ** hook returning non-zero, just as it would be with any other rollback.
  **
  ** ^For the purposes of this API, a transaction is said to have been
  ** rolled back if an explicit "ROLLBACK" statement is executed, or
  ** an error or constraint causes an implicit rollback to occur.
  ** ^The rollback callback is not invoked if a transaction is
  ** automatically rolled back because the database connection is closed.
  **
  ** See also the [sqlite3_update_hook()] interface.
  */
  SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
  SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
  
  /*
  ** CAPI3REF: Data Change Notification Callbacks
  ** METHOD: sqlite3
  **
  ** ^The sqlite3_update_hook() interface registers a callback function
  ** with the [database connection] identified by the first argument
  ** to be invoked whenever a row is updated, inserted or deleted in
  ** a [rowid table].
  ** ^Any callback set by a previous call to this function
  ** for the same database connection is overridden.
  **
  ** ^The second argument is a pointer to the function to invoke when a
  ** row is updated, inserted or deleted in a rowid table.
  ** ^The first argument to the callback is a copy of the third argument
  ** to sqlite3_update_hook().
  ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
  ** or [SQLITE_UPDATE], depending on the operation that caused the callback
  ** to be invoked.
  ** ^The third and fourth arguments to the callback contain pointers to the
  ** database and table name containing the affected row.
  ** ^The final callback parameter is the [rowid] of the row.
  ** ^In the case of an update, this is the [rowid] after the update takes place.
  **
  ** ^(The update hook is not invoked when internal system tables are
  ** modified (i.e. sqlite_sequence).)^
  ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
  **
  ** ^In the current implementation, the update hook
  ** is not invoked when conflicting rows are deleted because of an
  ** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
  ** invoked when rows are deleted using the [truncate optimization].
  ** The exceptions defined in this paragraph might change in a future
  ** release of SQLite.
  **
  ** The update hook implementation must not do anything that will modify
  ** the database connection that invoked the update hook.  Any actions
  ** to modify the database connection must be deferred until after the
  ** completion of the [sqlite3_step()] call that triggered the update hook.
  ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
  ** database connections for the meaning of "modify" in this paragraph.
  **
  ** ^The sqlite3_update_hook(D,C,P) function
  ** returns the P argument from the previous call
  ** on the same [database connection] D, or NULL for
  ** the first call on D.
  **
  ** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
  ** and [sqlite3_preupdate_hook()] interfaces.
  */
  SQLITE_API void *sqlite3_update_hook(
    sqlite3*,
    void(*)(void *,int ,char const *,char const *,sqlite3_int64),
    void*
  );
  
  /*
  ** CAPI3REF: Enable Or Disable Shared Pager Cache
  **
  ** ^(This routine enables or disables the sharing of the database cache
  ** and schema data structures between [database connection | connections]
  ** to the same database. Sharing is enabled if the argument is true
  ** and disabled if the argument is false.)^
  **
  ** ^Cache sharing is enabled and disabled for an entire process.
  ** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
  ** In prior versions of SQLite,
  ** sharing was enabled or disabled for each thread separately.
  **
  ** ^(The cache sharing mode set by this interface effects all subsequent
  ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
  ** Existing database connections continue to use the sharing mode
  ** that was in effect at the time they were opened.)^
  **
  ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
  ** successfully.  An [error code] is returned otherwise.)^
  **
  ** ^Shared cache is disabled by default. It is recommended that it stay
  ** that way.  In other words, do not use this routine.  This interface
  ** continues to be provided for historical compatibility, but its use is
  ** discouraged.  Any use of shared cache is discouraged.  If shared cache
  ** must be used, it is recommended that shared cache only be enabled for
  ** individual database connections using the [sqlite3_open_v2()] interface
  ** with the [SQLITE_OPEN_SHAREDCACHE] flag.
  **
  ** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
  ** and will always return SQLITE_MISUSE. On those systems,
  ** shared cache mode should be enabled per-database connection via
  ** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
  **
  ** This interface is threadsafe on processors where writing a
  ** 32-bit integer is atomic.
  **
  ** See Also:  [SQLite Shared-Cache Mode]
  */
  SQLITE_API int sqlite3_enable_shared_cache(int);
  
  /*
  ** CAPI3REF: Attempt To Free Heap Memory
  **
  ** ^The sqlite3_release_memory() interface attempts to free N bytes
  ** of heap memory by deallocating non-essential memory allocations
  ** held by the database library.   Memory used to cache database
  ** pages to improve performance is an example of non-essential memory.
  ** ^sqlite3_release_memory() returns the number of bytes actually freed,
  ** which might be more or less than the amount requested.
  ** ^The sqlite3_release_memory() routine is a no-op returning zero
  ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
  **
  ** See also: [sqlite3_db_release_memory()]
  */
  SQLITE_API int sqlite3_release_memory(int);
  
  /*
  ** CAPI3REF: Free Memory Used By A Database Connection
  ** METHOD: sqlite3
  **
  ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
  ** memory as possible from database connection D. Unlike the
  ** [sqlite3_release_memory()] interface, this interface is in effect even
  ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
  ** omitted.
  **
  ** See also: [sqlite3_release_memory()]
  */
  SQLITE_API int sqlite3_db_release_memory(sqlite3*);
  
  /*
  ** CAPI3REF: Impose A Limit On Heap Size
  **
  ** These interfaces impose limits on the amount of heap memory that will be
  ** by all database connections within a single process.
  **
  ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
  ** soft limit on the amount of heap memory that may be allocated by SQLite.
  ** ^SQLite strives to keep heap memory utilization below the soft heap
  ** limit by reducing the number of pages held in the page cache
  ** as heap memory usages approaches the limit.
  ** ^The soft heap limit is "soft" because even though SQLite strives to stay
  ** below the limit, it will exceed the limit rather than generate
  ** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
  ** is advisory only.
  **
  ** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
  ** N bytes on the amount of memory that will be allocated.  ^The
  ** sqlite3_hard_heap_limit64(N) interface is similar to
  ** sqlite3_soft_heap_limit64(N) except that memory allocations will fail
  ** when the hard heap limit is reached.
  **
  ** ^The return value from both sqlite3_soft_heap_limit64() and
  ** sqlite3_hard_heap_limit64() is the size of
  ** the heap limit prior to the call, or negative in the case of an
  ** error.  ^If the argument N is negative
  ** then no change is made to the heap limit.  Hence, the current
  ** size of heap limits can be determined by invoking
  ** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).
  **
  ** ^Setting the heap limits to zero disables the heap limiter mechanism.
  **
  ** ^The soft heap limit may not be greater than the hard heap limit.
  ** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
  ** is invoked with a value of N that is greater than the hard heap limit,
  ** the the soft heap limit is set to the value of the hard heap limit.
  ** ^The soft heap limit is automatically enabled whenever the hard heap
  ** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and
  ** the soft heap limit is outside the range of 1..N, then the soft heap
  ** limit is set to N.  ^Invoking sqlite3_soft_heap_limit64(0) when the
  ** hard heap limit is enabled makes the soft heap limit equal to the
  ** hard heap limit.
  **
  ** The memory allocation limits can also be adjusted using
  ** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit].
  **
  ** ^(The heap limits are not enforced in the current implementation
  ** if one or more of following conditions are true:
  **
  ** <ul>
  ** <li> The limit value is set to zero.
  ** <li> Memory accounting is disabled using a combination of the
  **      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
  **      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
  ** <li> An alternative page cache implementation is specified using
  **      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
  ** <li> The page cache allocates from its own memory pool supplied
  **      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
  **      from the heap.
  ** </ul>)^
  **
  ** The circumstances under which SQLite will enforce the heap limits may
  ** changes in future releases of SQLite.
  */
  SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
  SQLITE_API sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
  
  /*
  ** CAPI3REF: Deprecated Soft Heap Limit Interface
  ** DEPRECATED
  **
  ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
  ** interface.  This routine is provided for historical compatibility
  ** only.  All new applications should use the
  ** [sqlite3_soft_heap_limit64()] interface rather than this one.
  */
  SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
  
  
  /*
  ** CAPI3REF: Extract Metadata About A Column Of A Table
  ** METHOD: sqlite3
  **
  ** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
  ** information about column C of table T in database D
  ** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
  ** interface returns SQLITE_OK and fills in the non-NULL pointers in
  ** the final five arguments with appropriate values if the specified
  ** column exists.  ^The sqlite3_table_column_metadata() interface returns
  ** SQLITE_ERROR if the specified column does not exist.
  ** ^If the column-name parameter to sqlite3_table_column_metadata() is a
  ** NULL pointer, then this routine simply checks for the existence of the
  ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
  ** does not.  If the table name parameter T in a call to
  ** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
  ** undefined behavior.
  **
  ** ^The column is identified by the second, third and fourth parameters to
  ** this function. ^(The second parameter is either the name of the database
  ** (i.e. "main", "temp", or an attached database) containing the specified
  ** table or NULL.)^ ^If it is NULL, then all attached databases are searched
  ** for the table using the same algorithm used by the database engine to
  ** resolve unqualified table references.
  **
  ** ^The third and fourth parameters to this function are the table and column
  ** name of the desired column, respectively.
  **
  ** ^Metadata is returned by writing to the memory locations passed as the 5th
  ** and subsequent parameters to this function. ^Any of these arguments may be
  ** NULL, in which case the corresponding element of metadata is omitted.
  **
  ** ^(<blockquote>
  ** <table border="1">
  ** <tr><th> Parameter <th> Output<br>Type <th>  Description
  **
  ** <tr><td> 5th <td> const char* <td> Data type
  ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
  ** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
  ** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
  ** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
  ** </table>
  ** </blockquote>)^
  **
  ** ^The memory pointed to by the character pointers returned for the
  ** declaration type and collation sequence is valid until the next
  ** call to any SQLite API function.
  **
  ** ^If the specified table is actually a view, an [error code] is returned.
  **
  ** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
  ** is not a [WITHOUT ROWID] table and an
  ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
  ** parameters are set for the explicitly declared column. ^(If there is no
  ** [INTEGER PRIMARY KEY] column, then the outputs
  ** for the [rowid] are set as follows:
  **
  ** <pre>
  **     data type: "INTEGER"
  **     collation sequence: "BINARY"
  **     not null: 0
  **     primary key: 1
  **     auto increment: 0
  ** </pre>)^
  **
  ** ^This function causes all database schemas to be read from disk and
  ** parsed, if that has not already been done, and returns an error if
  ** any errors are encountered while loading the schema.
  */
  SQLITE_API int sqlite3_table_column_metadata(
    sqlite3 *db,                /* Connection handle */
    const char *zDbName,        /* Database name or NULL */
    const char *zTableName,     /* Table name */
    const char *zColumnName,    /* Column name */
    char const **pzDataType,    /* OUTPUT: Declared data type */
    char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
    int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
    int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
    int *pAutoinc               /* OUTPUT: True if column is auto-increment */
  );
  
  /*
  ** CAPI3REF: Load An Extension
  ** METHOD: sqlite3
  **
  ** ^This interface loads an SQLite extension library from the named file.
  **
  ** ^The sqlite3_load_extension() interface attempts to load an
  ** [SQLite extension] library contained in the file zFile.  If
  ** the file cannot be loaded directly, attempts are made to load
  ** with various operating-system specific extensions added.
  ** So for example, if "samplelib" cannot be loaded, then names like
  ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
  ** be tried also.
  **
  ** ^The entry point is zProc.
  ** ^(zProc may be 0, in which case SQLite will try to come up with an
  ** entry point name on its own.  It first tries "sqlite3_extension_init".
  ** If that does not work, it constructs a name "sqlite3_X_init" where the
  ** X is consists of the lower-case equivalent of all ASCII alphabetic
  ** characters in the filename from the last "/" to the first following
  ** "." and omitting any initial "lib".)^
  ** ^The sqlite3_load_extension() interface returns
  ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
  ** ^If an error occurs and pzErrMsg is not 0, then the
  ** [sqlite3_load_extension()] interface shall attempt to
  ** fill *pzErrMsg with error message text stored in memory
  ** obtained from [sqlite3_malloc()]. The calling function
  ** should free this memory by calling [sqlite3_free()].
  **
  ** ^Extension loading must be enabled using
  ** [sqlite3_enable_load_extension()] or
  ** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
  ** prior to calling this API,
  ** otherwise an error will be returned.
  **
  ** <b>Security warning:</b> It is recommended that the
  ** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
  ** interface.  The use of the [sqlite3_enable_load_extension()] interface
  ** should be avoided.  This will keep the SQL function [load_extension()]
  ** disabled and prevent SQL injections from giving attackers
  ** access to extension loading capabilities.
  **
  ** See also the [load_extension() SQL function].
  */
  SQLITE_API int sqlite3_load_extension(
    sqlite3 *db,          /* Load the extension into this database connection */
    const char *zFile,    /* Name of the shared library containing extension */
    const char *zProc,    /* Entry point.  Derived from zFile if 0 */
    char **pzErrMsg       /* Put error message here if not 0 */
  );
  
  /*
  ** CAPI3REF: Enable Or Disable Extension Loading
  ** METHOD: sqlite3
  **
  ** ^So as not to open security holes in older applications that are
  ** unprepared to deal with [extension loading], and as a means of disabling
  ** [extension loading] while evaluating user-entered SQL, the following API
  ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
  **
  ** ^Extension loading is off by default.
  ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
  ** to turn extension loading on and call it with onoff==0 to turn
  ** it back off again.
  **
  ** ^This interface enables or disables both the C-API
  ** [sqlite3_load_extension()] and the SQL function [load_extension()].
  ** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
  ** to enable or disable only the C-API.)^
  **
  ** <b>Security warning:</b> It is recommended that extension loading
  ** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
  ** rather than this interface, so the [load_extension()] SQL function
  ** remains disabled. This will prevent SQL injections from giving attackers
  ** access to extension loading capabilities.
  */
  SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
  
  /*
  ** CAPI3REF: Automatically Load Statically Linked Extensions
  **
  ** ^This interface causes the xEntryPoint() function to be invoked for
  ** each new [database connection] that is created.  The idea here is that
  ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
  ** that is to be automatically loaded into all new database connections.
  **
  ** ^(Even though the function prototype shows that xEntryPoint() takes
  ** no arguments and returns void, SQLite invokes xEntryPoint() with three
  ** arguments and expects an integer result as if the signature of the
  ** entry point where as follows:
  **
  ** <blockquote><pre>
  ** &nbsp;  int xEntryPoint(
  ** &nbsp;    sqlite3 *db,
  ** &nbsp;    const char **pzErrMsg,
  ** &nbsp;    const struct sqlite3_api_routines *pThunk
  ** &nbsp;  );
  ** </pre></blockquote>)^
  **
  ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
  ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
  ** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
  ** is NULL before calling the xEntryPoint().  ^SQLite will invoke
  ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
  ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
  ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
  **
  ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
  ** on the list of automatic extensions is a harmless no-op. ^No entry point
  ** will be called more than once for each database connection that is opened.
  **
  ** See also: [sqlite3_reset_auto_extension()]
  ** and [sqlite3_cancel_auto_extension()]
  */
  SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
  
  /*
  ** CAPI3REF: Cancel Automatic Extension Loading
  **
  ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
  ** initialization routine X that was registered using a prior call to
  ** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
  ** routine returns 1 if initialization routine X was successfully
  ** unregistered and it returns 0 if X was not on the list of initialization
  ** routines.
  */
  SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
  
  /*
  ** CAPI3REF: Reset Automatic Extension Loading
  **
  ** ^This interface disables all automatic extensions previously
  ** registered using [sqlite3_auto_extension()].
  */
  SQLITE_API void sqlite3_reset_auto_extension(void);
  
  /*
  ** The interface to the virtual-table mechanism is currently considered
  ** to be experimental.  The interface might change in incompatible ways.
  ** If this is a problem for you, do not use the interface at this time.
  **
  ** When the virtual-table mechanism stabilizes, we will declare the
  ** interface fixed, support it indefinitely, and remove this comment.
  */
  
  /*
  ** Structures used by the virtual table interface
  */
  typedef struct sqlite3_vtab sqlite3_vtab;
  typedef struct sqlite3_index_info sqlite3_index_info;
  typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
  typedef struct sqlite3_module sqlite3_module;
  
  /*
  ** CAPI3REF: Virtual Table Object
  ** KEYWORDS: sqlite3_module {virtual table module}
  **
  ** This structure, sometimes called a "virtual table module",
  ** defines the implementation of a [virtual table].
  ** This structure consists mostly of methods for the module.
  **
  ** ^A virtual table module is created by filling in a persistent
  ** instance of this structure and passing a pointer to that instance
  ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
  ** ^The registration remains valid until it is replaced by a different
  ** module or until the [database connection] closes.  The content
  ** of this structure must not change while it is registered with
  ** any database connection.
  */
  struct sqlite3_module {
    int iVersion;
    int (*xCreate)(sqlite3*, void *pAux,
                 int argc, const char *const*argv,
                 sqlite3_vtab **ppVTab, char**);
    int (*xConnect)(sqlite3*, void *pAux,
                 int argc, const char *const*argv,
                 sqlite3_vtab **ppVTab, char**);
    int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
    int (*xDisconnect)(sqlite3_vtab *pVTab);
    int (*xDestroy)(sqlite3_vtab *pVTab);
    int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
    int (*xClose)(sqlite3_vtab_cursor*);
    int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
                  int argc, sqlite3_value **argv);
    int (*xNext)(sqlite3_vtab_cursor*);
    int (*xEof)(sqlite3_vtab_cursor*);
    int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
    int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
    int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
    int (*xBegin)(sqlite3_vtab *pVTab);
    int (*xSync)(sqlite3_vtab *pVTab);
    int (*xCommit)(sqlite3_vtab *pVTab);
    int (*xRollback)(sqlite3_vtab *pVTab);
    int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
                         void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
                         void **ppArg);
    int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
    /* The methods above are in version 1 of the sqlite_module object. Those
    ** below are for version 2 and greater. */
    int (*xSavepoint)(sqlite3_vtab *pVTab, int);
    int (*xRelease)(sqlite3_vtab *pVTab, int);
    int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
    /* The methods above are in versions 1 and 2 of the sqlite_module object.
    ** Those below are for version 3 and greater. */
    int (*xShadowName)(const char*);
  };
  
  /*
  ** CAPI3REF: Virtual Table Indexing Information
  ** KEYWORDS: sqlite3_index_info
  **
  ** The sqlite3_index_info structure and its substructures is used as part
  ** of the [virtual table] interface to
  ** pass information into and receive the reply from the [xBestIndex]
  ** method of a [virtual table module].  The fields under **Inputs** are the
  ** inputs to xBestIndex and are read-only.  xBestIndex inserts its
  ** results into the **Outputs** fields.
  **
  ** ^(The aConstraint[] array records WHERE clause constraints of the form:
  **
  ** <blockquote>column OP expr</blockquote>
  **
  ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
  ** stored in aConstraint[].op using one of the
  ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
  ** ^(The index of the column is stored in
  ** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
  ** expr on the right-hand side can be evaluated (and thus the constraint
  ** is usable) and false if it cannot.)^
  **
  ** ^The optimizer automatically inverts terms of the form "expr OP column"
  ** and makes other simplifications to the WHERE clause in an attempt to
  ** get as many WHERE clause terms into the form shown above as possible.
  ** ^The aConstraint[] array only reports WHERE clause terms that are
  ** relevant to the particular virtual table being queried.
  **
  ** ^Information about the ORDER BY clause is stored in aOrderBy[].
  ** ^Each term of aOrderBy records a column of the ORDER BY clause.
  **
  ** The colUsed field indicates which columns of the virtual table may be
  ** required by the current scan. Virtual table columns are numbered from
  ** zero in the order in which they appear within the CREATE TABLE statement
  ** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
  ** the corresponding bit is set within the colUsed mask if the column may be
  ** required by SQLite. If the table has at least 64 columns and any column
  ** to the right of the first 63 is required, then bit 63 of colUsed is also
  ** set. In other words, column iCol may be required if the expression
  ** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
  ** non-zero.
  **
  ** The [xBestIndex] method must fill aConstraintUsage[] with information
  ** about what parameters to pass to xFilter.  ^If argvIndex>0 then
  ** the right-hand side of the corresponding aConstraint[] is evaluated
  ** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
  ** is true, then the constraint is assumed to be fully handled by the
  ** virtual table and might not be checked again by the byte code.)^ ^(The
  ** aConstraintUsage[].omit flag is an optimization hint. When the omit flag
  ** is left in its default setting of false, the constraint will always be
  ** checked separately in byte code.  If the omit flag is change to true, then
  ** the constraint may or may not be checked in byte code.  In other words,
  ** when the omit flag is true there is no guarantee that the constraint will
  ** not be checked again using byte code.)^
  **
  ** ^The idxNum and idxPtr values are recorded and passed into the
  ** [xFilter] method.
  ** ^[sqlite3_free()] is used to free idxPtr if and only if
  ** needToFreeIdxPtr is true.
  **
  ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
  ** the correct order to satisfy the ORDER BY clause so that no separate
  ** sorting step is required.
  **
  ** ^The estimatedCost value is an estimate of the cost of a particular
  ** strategy. A cost of N indicates that the cost of the strategy is similar
  ** to a linear scan of an SQLite table with N rows. A cost of log(N)
  ** indicates that the expense of the operation is similar to that of a
  ** binary search on a unique indexed field of an SQLite table with N rows.
  **
  ** ^The estimatedRows value is an estimate of the number of rows that
  ** will be returned by the strategy.
  **
  ** The xBestIndex method may optionally populate the idxFlags field with a
  ** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
  ** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
  ** assumes that the strategy may visit at most one row.
  **
  ** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
  ** SQLite also assumes that if a call to the xUpdate() method is made as
  ** part of the same statement to delete or update a virtual table row and the
  ** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
  ** any database changes. In other words, if the xUpdate() returns
  ** SQLITE_CONSTRAINT, the database contents must be exactly as they were
  ** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
  ** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
  ** the xUpdate method are automatically rolled back by SQLite.
  **
  ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
  ** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
  ** If a virtual table extension is
  ** used with an SQLite version earlier than 3.8.2, the results of attempting
  ** to read or write the estimatedRows field are undefined (but are likely
  ** to include crashing the application). The estimatedRows field should
  ** therefore only be used if [sqlite3_libversion_number()] returns a
  ** value greater than or equal to 3008002. Similarly, the idxFlags field
  ** was added for [version 3.9.0] ([dateof:3.9.0]).
  ** It may therefore only be used if
  ** sqlite3_libversion_number() returns a value greater than or equal to
  ** 3009000.
  */
  struct sqlite3_index_info {
    /* Inputs */
    int nConstraint;           /* Number of entries in aConstraint */
    struct sqlite3_index_constraint {
       int iColumn;              /* Column constrained.  -1 for ROWID */
       unsigned char op;         /* Constraint operator */
       unsigned char usable;     /* True if this constraint is usable */
       int iTermOffset;          /* Used internally - xBestIndex should ignore */
    } *aConstraint;            /* Table of WHERE clause constraints */
    int nOrderBy;              /* Number of terms in the ORDER BY clause */
    struct sqlite3_index_orderby {
       int iColumn;              /* Column number */
       unsigned char desc;       /* True for DESC.  False for ASC. */
    } *aOrderBy;               /* The ORDER BY clause */
    /* Outputs */
    struct sqlite3_index_constraint_usage {
      int argvIndex;           /* if >0, constraint is part of argv to xFilter */
      unsigned char omit;      /* Do not code a test for this constraint */
    } *aConstraintUsage;
    int idxNum;                /* Number used to identify the index */
    char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
    int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
    int orderByConsumed;       /* True if output is already ordered */
    double estimatedCost;           /* Estimated cost of using this index */
    /* Fields below are only available in SQLite 3.8.2 and later */
    sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
    /* Fields below are only available in SQLite 3.9.0 and later */
    int idxFlags;              /* Mask of SQLITE_INDEX_SCAN_* flags */
    /* Fields below are only available in SQLite 3.10.0 and later */
    sqlite3_uint64 colUsed;    /* Input: Mask of columns used by statement */
  };
  
  /*
  ** CAPI3REF: Virtual Table Scan Flags
  **
  ** Virtual table implementations are allowed to set the
  ** [sqlite3_index_info].idxFlags field to some combination of
  ** these bits.
  */
  #define SQLITE_INDEX_SCAN_UNIQUE      1     /* Scan visits at most 1 row */
  
  /*
  ** CAPI3REF: Virtual Table Constraint Operator Codes
  **
  ** These macros define the allowed values for the
  ** [sqlite3_index_info].aConstraint[].op field.  Each value represents
  ** an operator that is part of a constraint term in the wHERE clause of
  ** a query that uses a [virtual table].
  */
  #define SQLITE_INDEX_CONSTRAINT_EQ         2
  #define SQLITE_INDEX_CONSTRAINT_GT         4
  #define SQLITE_INDEX_CONSTRAINT_LE         8
  #define SQLITE_INDEX_CONSTRAINT_LT        16
  #define SQLITE_INDEX_CONSTRAINT_GE        32
  #define SQLITE_INDEX_CONSTRAINT_MATCH     64
  #define SQLITE_INDEX_CONSTRAINT_LIKE      65
  #define SQLITE_INDEX_CONSTRAINT_GLOB      66
  #define SQLITE_INDEX_CONSTRAINT_REGEXP    67
  #define SQLITE_INDEX_CONSTRAINT_NE        68
  #define SQLITE_INDEX_CONSTRAINT_ISNOT     69
  #define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
  #define SQLITE_INDEX_CONSTRAINT_ISNULL    71
  #define SQLITE_INDEX_CONSTRAINT_IS        72
  #define SQLITE_INDEX_CONSTRAINT_FUNCTION 150
  
  /*
  ** CAPI3REF: Register A Virtual Table Implementation
  ** METHOD: sqlite3
  **
  ** ^These routines are used to register a new [virtual table module] name.
  ** ^Module names must be registered before
  ** creating a new [virtual table] using the module and before using a
  ** preexisting [virtual table] for the module.
  **
  ** ^The module name is registered on the [database connection] specified
  ** by the first parameter.  ^The name of the module is given by the
  ** second parameter.  ^The third parameter is a pointer to
  ** the implementation of the [virtual table module].   ^The fourth
  ** parameter is an arbitrary client data pointer that is passed through
  ** into the [xCreate] and [xConnect] methods of the virtual table module
  ** when a new virtual table is be being created or reinitialized.
  **
  ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
  ** is a pointer to a destructor for the pClientData.  ^SQLite will
  ** invoke the destructor function (if it is not NULL) when SQLite
  ** no longer needs the pClientData pointer.  ^The destructor will also
  ** be invoked if the call to sqlite3_create_module_v2() fails.
  ** ^The sqlite3_create_module()
  ** interface is equivalent to sqlite3_create_module_v2() with a NULL
  ** destructor.
  **
  ** ^If the third parameter (the pointer to the sqlite3_module object) is
  ** NULL then no new module is create and any existing modules with the
  ** same name are dropped.
  **
  ** See also: [sqlite3_drop_modules()]
  */
  SQLITE_API int sqlite3_create_module(
    sqlite3 *db,               /* SQLite connection to register module with */
    const char *zName,         /* Name of the module */
    const sqlite3_module *p,   /* Methods for the module */
    void *pClientData          /* Client data for xCreate/xConnect */
  );
  SQLITE_API int sqlite3_create_module_v2(
    sqlite3 *db,               /* SQLite connection to register module with */
    const char *zName,         /* Name of the module */
    const sqlite3_module *p,   /* Methods for the module */
    void *pClientData,         /* Client data for xCreate/xConnect */
    void(*xDestroy)(void*)     /* Module destructor function */
  );
  
  /*
  ** CAPI3REF: Remove Unnecessary Virtual Table Implementations
  ** METHOD: sqlite3
  **
  ** ^The sqlite3_drop_modules(D,L) interface removes all virtual
  ** table modules from database connection D except those named on list L.
  ** The L parameter must be either NULL or a pointer to an array of pointers
  ** to strings where the array is terminated by a single NULL pointer.
  ** ^If the L parameter is NULL, then all virtual table modules are removed.
  **
  ** See also: [sqlite3_create_module()]
  */
  SQLITE_API int sqlite3_drop_modules(
    sqlite3 *db,                /* Remove modules from this connection */
    const char **azKeep         /* Except, do not remove the ones named here */
  );
  
  /*
  ** CAPI3REF: Virtual Table Instance Object
  ** KEYWORDS: sqlite3_vtab
  **
  ** Every [virtual table module] implementation uses a subclass
  ** of this object to describe a particular instance
  ** of the [virtual table].  Each subclass will
  ** be tailored to the specific needs of the module implementation.
  ** The purpose of this superclass is to define certain fields that are
  ** common to all module implementations.
  **
  ** ^Virtual tables methods can set an error message by assigning a
  ** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
  ** take care that any prior string is freed by a call to [sqlite3_free()]
  ** prior to assigning a new string to zErrMsg.  ^After the error message
  ** is delivered up to the client application, the string will be automatically
  ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
  */
  struct sqlite3_vtab {
    const sqlite3_module *pModule;  /* The module for this virtual table */
    int nRef;                       /* Number of open cursors */
    char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
    /* Virtual table implementations will typically add additional fields */
  };
  
  /*
  ** CAPI3REF: Virtual Table Cursor Object
  ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
  **
  ** Every [virtual table module] implementation uses a subclass of the
  ** following structure to describe cursors that point into the
  ** [virtual table] and are used
  ** to loop through the virtual table.  Cursors are created using the
  ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
  ** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
  ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
  ** of the module.  Each module implementation will define
  ** the content of a cursor structure to suit its own needs.
  **
  ** This superclass exists in order to define fields of the cursor that
  ** are common to all implementations.
  */
  struct sqlite3_vtab_cursor {
    sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
    /* Virtual table implementations will typically add additional fields */
  };
  
  /*
  ** CAPI3REF: Declare The Schema Of A Virtual Table
  **
  ** ^The [xCreate] and [xConnect] methods of a
  ** [virtual table module] call this interface
  ** to declare the format (the names and datatypes of the columns) of
  ** the virtual tables they implement.
  */
  SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
  
  /*
  ** CAPI3REF: Overload A Function For A Virtual Table
  ** METHOD: sqlite3
  **
  ** ^(Virtual tables can provide alternative implementations of functions
  ** using the [xFindFunction] method of the [virtual table module].
  ** But global versions of those functions
  ** must exist in order to be overloaded.)^
  **
  ** ^(This API makes sure a global version of a function with a particular
  ** name and number of parameters exists.  If no such function exists
  ** before this API is called, a new function is created.)^  ^The implementation
  ** of the new function always causes an exception to be thrown.  So
  ** the new function is not good for anything by itself.  Its only
  ** purpose is to be a placeholder function that can be overloaded
  ** by a [virtual table].
  */
  SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
  
  /*
  ** The interface to the virtual-table mechanism defined above (back up
  ** to a comment remarkably similar to this one) is currently considered
  ** to be experimental.  The interface might change in incompatible ways.
  ** If this is a problem for you, do not use the interface at this time.
  **
  ** When the virtual-table mechanism stabilizes, we will declare the
  ** interface fixed, support it indefinitely, and remove this comment.
  */
  
  /*
  ** CAPI3REF: A Handle To An Open BLOB
  ** KEYWORDS: {BLOB handle} {BLOB handles}
  **
  ** An instance of this object represents an open BLOB on which
  ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
  ** ^Objects of this type are created by [sqlite3_blob_open()]
  ** and destroyed by [sqlite3_blob_close()].
  ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
  ** can be used to read or write small subsections of the BLOB.
  ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
  */
  typedef struct sqlite3_blob sqlite3_blob;
  
  /*
  ** CAPI3REF: Open A BLOB For Incremental I/O
  ** METHOD: sqlite3
  ** CONSTRUCTOR: sqlite3_blob
  **
  ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
  ** in row iRow, column zColumn, table zTable in database zDb;
  ** in other words, the same BLOB that would be selected by:
  **
  ** <pre>
  **     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
  ** </pre>)^
  **
  ** ^(Parameter zDb is not the filename that contains the database, but
  ** rather the symbolic name of the database. For attached databases, this is
  ** the name that appears after the AS keyword in the [ATTACH] statement.
  ** For the main database file, the database name is "main". For TEMP
  ** tables, the database name is "temp".)^
  **
  ** ^If the flags parameter is non-zero, then the BLOB is opened for read
  ** and write access. ^If the flags parameter is zero, the BLOB is opened for
  ** read-only access.
  **
  ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
  ** in *ppBlob. Otherwise an [error code] is returned and, unless the error
  ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
  ** the API is not misused, it is always safe to call [sqlite3_blob_close()]
  ** on *ppBlob after this function it returns.
  **
  ** This function fails with SQLITE_ERROR if any of the following are true:
  ** <ul>
  **   <li> ^(Database zDb does not exist)^,
  **   <li> ^(Table zTable does not exist within database zDb)^,
  **   <li> ^(Table zTable is a WITHOUT ROWID table)^,
  **   <li> ^(Column zColumn does not exist)^,
  **   <li> ^(Row iRow is not present in the table)^,
  **   <li> ^(The specified column of row iRow contains a value that is not
  **         a TEXT or BLOB value)^,
  **   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
  **         constraint and the blob is being opened for read/write access)^,
  **   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
  **         column zColumn is part of a [child key] definition and the blob is
  **         being opened for read/write access)^.
  ** </ul>
  **
  ** ^Unless it returns SQLITE_MISUSE, this function sets the
  ** [database connection] error code and message accessible via
  ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
  **
  ** A BLOB referenced by sqlite3_blob_open() may be read using the
  ** [sqlite3_blob_read()] interface and modified by using
  ** [sqlite3_blob_write()].  The [BLOB handle] can be moved to a
  ** different row of the same table using the [sqlite3_blob_reopen()]
  ** interface.  However, the column, table, or database of a [BLOB handle]
  ** cannot be changed after the [BLOB handle] is opened.
  **
  ** ^(If the row that a BLOB handle points to is modified by an
  ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
  ** then the BLOB handle is marked as "expired".
  ** This is true if any column of the row is changed, even a column
  ** other than the one the BLOB handle is open on.)^
  ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
  ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
  ** ^(Changes written into a BLOB prior to the BLOB expiring are not
  ** rolled back by the expiration of the BLOB.  Such changes will eventually
  ** commit if the transaction continues to completion.)^
  **
  ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
  ** the opened blob.  ^The size of a blob may not be changed by this
  ** interface.  Use the [UPDATE] SQL command to change the size of a
  ** blob.
  **
  ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
  ** and the built-in [zeroblob] SQL function may be used to create a
  ** zero-filled blob to read or write using the incremental-blob interface.
  **
  ** To avoid a resource leak, every open [BLOB handle] should eventually
  ** be released by a call to [sqlite3_blob_close()].
  **
  ** See also: [sqlite3_blob_close()],
  ** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
  ** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
  */
  SQLITE_API int sqlite3_blob_open(
    sqlite3*,
    const char *zDb,
    const char *zTable,
    const char *zColumn,
    sqlite3_int64 iRow,
    int flags,
    sqlite3_blob **ppBlob
  );
  
  /*
  ** CAPI3REF: Move a BLOB Handle to a New Row
  ** METHOD: sqlite3_blob
  **
  ** ^This function is used to move an existing [BLOB handle] so that it points
  ** to a different row of the same database table. ^The new row is identified
  ** by the rowid value passed as the second argument. Only the row can be
  ** changed. ^The database, table and column on which the blob handle is open
  ** remain the same. Moving an existing [BLOB handle] to a new row is
  ** faster than closing the existing handle and opening a new one.
  **
  ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
  ** it must exist and there must be either a blob or text value stored in
  ** the nominated column.)^ ^If the new row is not present in the table, or if
  ** it does not contain a blob or text value, or if another error occurs, an
  ** SQLite error code is returned and the blob handle is considered aborted.
  ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
  ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
  ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
  ** always returns zero.
  **
  ** ^This function sets the database handle error code and message.
  */
  SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
  
  /*
  ** CAPI3REF: Close A BLOB Handle
  ** DESTRUCTOR: sqlite3_blob
  **
  ** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
  ** unconditionally.  Even if this routine returns an error code, the
  ** handle is still closed.)^
  **
  ** ^If the blob handle being closed was opened for read-write access, and if
  ** the database is in auto-commit mode and there are no other open read-write
  ** blob handles or active write statements, the current transaction is
  ** committed. ^If an error occurs while committing the transaction, an error
  ** code is returned and the transaction rolled back.
  **
  ** Calling this function with an argument that is not a NULL pointer or an
  ** open blob handle results in undefined behaviour. ^Calling this routine
  ** with a null pointer (such as would be returned by a failed call to
  ** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
  ** is passed a valid open blob handle, the values returned by the
  ** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
  */
  SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
  
  /*
  ** CAPI3REF: Return The Size Of An Open BLOB
  ** METHOD: sqlite3_blob
  **
  ** ^Returns the size in bytes of the BLOB accessible via the
  ** successfully opened [BLOB handle] in its only argument.  ^The
  ** incremental blob I/O routines can only read or overwriting existing
  ** blob content; they cannot change the size of a blob.
  **
  ** This routine only works on a [BLOB handle] which has been created
  ** by a prior successful call to [sqlite3_blob_open()] and which has not
  ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
  ** to this routine results in undefined and probably undesirable behavior.
  */
  SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
  
  /*
  ** CAPI3REF: Read Data From A BLOB Incrementally
  ** METHOD: sqlite3_blob
  **
  ** ^(This function is used to read data from an open [BLOB handle] into a
  ** caller-supplied buffer. N bytes of data are copied into buffer Z
  ** from the open BLOB, starting at offset iOffset.)^
  **
  ** ^If offset iOffset is less than N bytes from the end of the BLOB,
  ** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
  ** less than zero, [SQLITE_ERROR] is returned and no data is read.
  ** ^The size of the blob (and hence the maximum value of N+iOffset)
  ** can be determined using the [sqlite3_blob_bytes()] interface.
  **
  ** ^An attempt to read from an expired [BLOB handle] fails with an
  ** error code of [SQLITE_ABORT].
  **
  ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
  ** Otherwise, an [error code] or an [extended error code] is returned.)^
  **
  ** This routine only works on a [BLOB handle] which has been created
  ** by a prior successful call to [sqlite3_blob_open()] and which has not
  ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
  ** to this routine results in undefined and probably undesirable behavior.
  **
  ** See also: [sqlite3_blob_write()].
  */
  SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
  
  /*
  ** CAPI3REF: Write Data Into A BLOB Incrementally
  ** METHOD: sqlite3_blob
  **
  ** ^(This function is used to write data into an open [BLOB handle] from a
  ** caller-supplied buffer. N bytes of data are copied from the buffer Z
  ** into the open BLOB, starting at offset iOffset.)^
  **
  ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
  ** Otherwise, an  [error code] or an [extended error code] is returned.)^
  ** ^Unless SQLITE_MISUSE is returned, this function sets the
  ** [database connection] error code and message accessible via
  ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
  **
  ** ^If the [BLOB handle] passed as the first argument was not opened for
  ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
  ** this function returns [SQLITE_READONLY].
  **
  ** This function may only modify the contents of the BLOB; it is
  ** not possible to increase the size of a BLOB using this API.
  ** ^If offset iOffset is less than N bytes from the end of the BLOB,
  ** [SQLITE_ERROR] is returned and no data is written. The size of the
  ** BLOB (and hence the maximum value of N+iOffset) can be determined
  ** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
  ** than zero [SQLITE_ERROR] is returned and no data is written.
  **
  ** ^An attempt to write to an expired [BLOB handle] fails with an
  ** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
  ** before the [BLOB handle] expired are not rolled back by the
  ** expiration of the handle, though of course those changes might
  ** have been overwritten by the statement that expired the BLOB handle
  ** or by other independent statements.
  **
  ** This routine only works on a [BLOB handle] which has been created
  ** by a prior successful call to [sqlite3_blob_open()] and which has not
  ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
  ** to this routine results in undefined and probably undesirable behavior.
  **
  ** See also: [sqlite3_blob_read()].
  */
  SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
  
  /*
  ** CAPI3REF: Virtual File System Objects
  **
  ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
  ** that SQLite uses to interact
  ** with the underlying operating system.  Most SQLite builds come with a
  ** single default VFS that is appropriate for the host computer.
  ** New VFSes can be registered and existing VFSes can be unregistered.
  ** The following interfaces are provided.
  **
  ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
  ** ^Names are case sensitive.
  ** ^Names are zero-terminated UTF-8 strings.
  ** ^If there is no match, a NULL pointer is returned.
  ** ^If zVfsName is NULL then the default VFS is returned.
  **
  ** ^New VFSes are registered with sqlite3_vfs_register().
  ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
  ** ^The same VFS can be registered multiple times without injury.
  ** ^To make an existing VFS into the default VFS, register it again
  ** with the makeDflt flag set.  If two different VFSes with the
  ** same name are registered, the behavior is undefined.  If a
  ** VFS is registered with a name that is NULL or an empty string,
  ** then the behavior is undefined.
  **
  ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
  ** ^(If the default VFS is unregistered, another VFS is chosen as
  ** the default.  The choice for the new VFS is arbitrary.)^
  */
  SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
  SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
  SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
  
  /*
  ** CAPI3REF: Mutexes
  **
  ** The SQLite core uses these routines for thread
  ** synchronization. Though they are intended for internal
  ** use by SQLite, code that links against SQLite is
  ** permitted to use any of these routines.
  **
  ** The SQLite source code contains multiple implementations
  ** of these mutex routines.  An appropriate implementation
  ** is selected automatically at compile-time.  The following
  ** implementations are available in the SQLite core:
  **
  ** <ul>
  ** <li>   SQLITE_MUTEX_PTHREADS
  ** <li>   SQLITE_MUTEX_W32
  ** <li>   SQLITE_MUTEX_NOOP
  ** </ul>
  **
  ** The SQLITE_MUTEX_NOOP implementation is a set of routines
  ** that does no real locking and is appropriate for use in
  ** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
  ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
  ** and Windows.
  **
  ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
  ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
  ** implementation is included with the library. In this case the
  ** application must supply a custom mutex implementation using the
  ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
  ** before calling sqlite3_initialize() or any other public sqlite3_
  ** function that calls sqlite3_initialize().
  **
  ** ^The sqlite3_mutex_alloc() routine allocates a new
  ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
  ** routine returns NULL if it is unable to allocate the requested
  ** mutex.  The argument to sqlite3_mutex_alloc() must one of these
  ** integer constants:
  **
  ** <ul>
  ** <li>  SQLITE_MUTEX_FAST
  ** <li>  SQLITE_MUTEX_RECURSIVE
  ** <li>  SQLITE_MUTEX_STATIC_MAIN
  ** <li>  SQLITE_MUTEX_STATIC_MEM
  ** <li>  SQLITE_MUTEX_STATIC_OPEN
  ** <li>  SQLITE_MUTEX_STATIC_PRNG
  ** <li>  SQLITE_MUTEX_STATIC_LRU
  ** <li>  SQLITE_MUTEX_STATIC_PMEM
  ** <li>  SQLITE_MUTEX_STATIC_APP1
  ** <li>  SQLITE_MUTEX_STATIC_APP2
  ** <li>  SQLITE_MUTEX_STATIC_APP3
  ** <li>  SQLITE_MUTEX_STATIC_VFS1
  ** <li>  SQLITE_MUTEX_STATIC_VFS2
  ** <li>  SQLITE_MUTEX_STATIC_VFS3
  ** </ul>
  **
  ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
  ** cause sqlite3_mutex_alloc() to create
  ** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
  ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
  ** The mutex implementation does not need to make a distinction
  ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
  ** not want to.  SQLite will only request a recursive mutex in
  ** cases where it really needs one.  If a faster non-recursive mutex
  ** implementation is available on the host platform, the mutex subsystem
  ** might return such a mutex in response to SQLITE_MUTEX_FAST.
  **
  ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
  ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
  ** a pointer to a static preexisting mutex.  ^Nine static mutexes are
  ** used by the current version of SQLite.  Future versions of SQLite
  ** may add additional static mutexes.  Static mutexes are for internal
  ** use by SQLite only.  Applications that use SQLite mutexes should
  ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
  ** SQLITE_MUTEX_RECURSIVE.
  **
  ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
  ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
  ** returns a different mutex on every call.  ^For the static
  ** mutex types, the same mutex is returned on every call that has
  ** the same type number.
  **
  ** ^The sqlite3_mutex_free() routine deallocates a previously
  ** allocated dynamic mutex.  Attempting to deallocate a static
  ** mutex results in undefined behavior.
  **
  ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
  ** to enter a mutex.  ^If another thread is already within the mutex,
  ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
  ** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
  ** upon successful entry.  ^(Mutexes created using
  ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
  ** In such cases, the
  ** mutex must be exited an equal number of times before another thread
  ** can enter.)^  If the same thread tries to enter any mutex other
  ** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
  **
  ** ^(Some systems (for example, Windows 95) do not support the operation
  ** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
  ** will always return SQLITE_BUSY. The SQLite core only ever uses
  ** sqlite3_mutex_try() as an optimization so this is acceptable
  ** behavior.)^
  **
  ** ^The sqlite3_mutex_leave() routine exits a mutex that was
  ** previously entered by the same thread.   The behavior
  ** is undefined if the mutex is not currently entered by the
  ** calling thread or is not currently allocated.
  **
  ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
  ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
  ** behave as no-ops.
  **
  ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
  */
  SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
  SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
  SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
  SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
  SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
  
  /*
  ** CAPI3REF: Mutex Methods Object
  **
  ** An instance of this structure defines the low-level routines
  ** used to allocate and use mutexes.
  **
  ** Usually, the default mutex implementations provided by SQLite are
  ** sufficient, however the application has the option of substituting a custom
  ** implementation for specialized deployments or systems for which SQLite
  ** does not provide a suitable implementation. In this case, the application
  ** creates and populates an instance of this structure to pass
  ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
  ** Additionally, an instance of this structure can be used as an
  ** output variable when querying the system for the current mutex
  ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
  **
  ** ^The xMutexInit method defined by this structure is invoked as
  ** part of system initialization by the sqlite3_initialize() function.
  ** ^The xMutexInit routine is called by SQLite exactly once for each
  ** effective call to [sqlite3_initialize()].
  **
  ** ^The xMutexEnd method defined by this structure is invoked as
  ** part of system shutdown by the sqlite3_shutdown() function. The
  ** implementation of this method is expected to release all outstanding
  ** resources obtained by the mutex methods implementation, especially
  ** those obtained by the xMutexInit method.  ^The xMutexEnd()
  ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
  **
  ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
  ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
  ** xMutexNotheld) implement the following interfaces (respectively):
  **
  ** <ul>
  **   <li>  [sqlite3_mutex_alloc()] </li>
  **   <li>  [sqlite3_mutex_free()] </li>
  **   <li>  [sqlite3_mutex_enter()] </li>
  **   <li>  [sqlite3_mutex_try()] </li>
  **   <li>  [sqlite3_mutex_leave()] </li>
  **   <li>  [sqlite3_mutex_held()] </li>
  **   <li>  [sqlite3_mutex_notheld()] </li>
  ** </ul>)^
  **
  ** The only difference is that the public sqlite3_XXX functions enumerated
  ** above silently ignore any invocations that pass a NULL pointer instead
  ** of a valid mutex handle. The implementations of the methods defined
  ** by this structure are not required to handle this case. The results
  ** of passing a NULL pointer instead of a valid mutex handle are undefined
  ** (i.e. it is acceptable to provide an implementation that segfaults if
  ** it is passed a NULL pointer).
  **
  ** The xMutexInit() method must be threadsafe.  It must be harmless to
  ** invoke xMutexInit() multiple times within the same process and without
  ** intervening calls to xMutexEnd().  Second and subsequent calls to
  ** xMutexInit() must be no-ops.
  **
  ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
  ** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
  ** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
  ** memory allocation for a fast or recursive mutex.
  **
  ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
  ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
  ** If xMutexInit fails in any way, it is expected to clean up after itself
  ** prior to returning.
  */
  typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
  struct sqlite3_mutex_methods {
    int (*xMutexInit)(void);
    int (*xMutexEnd)(void);
    sqlite3_mutex *(*xMutexAlloc)(int);
    void (*xMutexFree)(sqlite3_mutex *);
    void (*xMutexEnter)(sqlite3_mutex *);
    int (*xMutexTry)(sqlite3_mutex *);
    void (*xMutexLeave)(sqlite3_mutex *);
    int (*xMutexHeld)(sqlite3_mutex *);
    int (*xMutexNotheld)(sqlite3_mutex *);
  };
  
  /*
  ** CAPI3REF: Mutex Verification Routines
  **
  ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
  ** are intended for use inside assert() statements.  The SQLite core
  ** never uses these routines except inside an assert() and applications
  ** are advised to follow the lead of the core.  The SQLite core only
  ** provides implementations for these routines when it is compiled
  ** with the SQLITE_DEBUG flag.  External mutex implementations
  ** are only required to provide these routines if SQLITE_DEBUG is
  ** defined and if NDEBUG is not defined.
  **
  ** These routines should return true if the mutex in their argument
  ** is held or not held, respectively, by the calling thread.
  **
  ** The implementation is not required to provide versions of these
  ** routines that actually work. If the implementation does not provide working
  ** versions of these routines, it should at least provide stubs that always
  ** return true so that one does not get spurious assertion failures.
  **
  ** If the argument to sqlite3_mutex_held() is a NULL pointer then
  ** the routine should return 1.   This seems counter-intuitive since
  ** clearly the mutex cannot be held if it does not exist.  But
  ** the reason the mutex does not exist is because the build is not
  ** using mutexes.  And we do not want the assert() containing the
  ** call to sqlite3_mutex_held() to fail, so a non-zero return is
  ** the appropriate thing to do.  The sqlite3_mutex_notheld()
  ** interface should also return 1 when given a NULL pointer.
  */
  #ifndef NDEBUG
  SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
  SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
  #endif
  
  /*
  ** CAPI3REF: Mutex Types
  **
  ** The [sqlite3_mutex_alloc()] interface takes a single argument
  ** which is one of these integer constants.
  **
  ** The set of static mutexes may change from one SQLite release to the
  ** next.  Applications that override the built-in mutex logic must be
  ** prepared to accommodate additional static mutexes.
  */
  #define SQLITE_MUTEX_FAST             0
  #define SQLITE_MUTEX_RECURSIVE        1
  #define SQLITE_MUTEX_STATIC_MAIN      2
  #define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
  #define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
  #define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
  #define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_randomness() */
  #define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
  #define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
  #define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
  #define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
  #define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
  #define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
  #define SQLITE_MUTEX_STATIC_VFS1     11  /* For use by built-in VFS */
  #define SQLITE_MUTEX_STATIC_VFS2     12  /* For use by extension VFS */
  #define SQLITE_MUTEX_STATIC_VFS3     13  /* For use by application VFS */
  
  /* Legacy compatibility: */
  #define SQLITE_MUTEX_STATIC_MASTER    2
  
  
  /*
  ** CAPI3REF: Retrieve the mutex for a database connection
  ** METHOD: sqlite3
  **
  ** ^This interface returns a pointer the [sqlite3_mutex] object that
  ** serializes access to the [database connection] given in the argument
  ** when the [threading mode] is Serialized.
  ** ^If the [threading mode] is Single-thread or Multi-thread then this
  ** routine returns a NULL pointer.
  */
  SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
  
  /*
  ** CAPI3REF: Low-Level Control Of Database Files
  ** METHOD: sqlite3
  ** KEYWORDS: {file control}
  **
  ** ^The [sqlite3_file_control()] interface makes a direct call to the
  ** xFileControl method for the [sqlite3_io_methods] object associated
  ** with a particular database identified by the second argument. ^The
  ** name of the database is "main" for the main database or "temp" for the
  ** TEMP database, or the name that appears after the AS keyword for
  ** databases that are added using the [ATTACH] SQL command.
  ** ^A NULL pointer can be used in place of "main" to refer to the
  ** main database file.
  ** ^The third and fourth parameters to this routine
  ** are passed directly through to the second and third parameters of
  ** the xFileControl method.  ^The return value of the xFileControl
  ** method becomes the return value of this routine.
  **
  ** A few opcodes for [sqlite3_file_control()] are handled directly
  ** by the SQLite core and never invoke the
  ** sqlite3_io_methods.xFileControl method.
  ** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
  ** a pointer to the underlying [sqlite3_file] object to be written into
  ** the space pointed to by the 4th parameter.  The
  ** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
  ** the [sqlite3_file] object associated with the journal file instead of
  ** the main database.  The [SQLITE_FCNTL_VFS_POINTER] opcode returns
  ** a pointer to the underlying [sqlite3_vfs] object for the file.
  ** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
  ** from the pager.
  **
  ** ^If the second parameter (zDbName) does not match the name of any
  ** open database file, then SQLITE_ERROR is returned.  ^This error
  ** code is not remembered and will not be recalled by [sqlite3_errcode()]
  ** or [sqlite3_errmsg()].  The underlying xFileControl method might
  ** also return SQLITE_ERROR.  There is no way to distinguish between
  ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
  ** xFileControl method.
  **
  ** See also: [file control opcodes]
  */
  SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
  
  /*
  ** CAPI3REF: Testing Interface
  **
  ** ^The sqlite3_test_control() interface is used to read out internal
  ** state of SQLite and to inject faults into SQLite for testing
  ** purposes.  ^The first parameter is an operation code that determines
  ** the number, meaning, and operation of all subsequent parameters.
  **
  ** This interface is not for use by applications.  It exists solely
  ** for verifying the correct operation of the SQLite library.  Depending
  ** on how the SQLite library is compiled, this interface might not exist.
  **
  ** The details of the operation codes, their meanings, the parameters
  ** they take, and what they do are all subject to change without notice.
  ** Unlike most of the SQLite API, this function is not guaranteed to
  ** operate consistently from one release to the next.
  */
  SQLITE_API int sqlite3_test_control(int op, ...);
  
  /*
  ** CAPI3REF: Testing Interface Operation Codes
  **
  ** These constants are the valid operation code parameters used
  ** as the first argument to [sqlite3_test_control()].
  **
  ** These parameters and their meanings are subject to change
  ** without notice.  These values are for testing purposes only.
  ** Applications should not use any of these parameters or the
  ** [sqlite3_test_control()] interface.
  */
  #define SQLITE_TESTCTRL_FIRST                    5
  #define SQLITE_TESTCTRL_PRNG_SAVE                5
  #define SQLITE_TESTCTRL_PRNG_RESTORE             6
  #define SQLITE_TESTCTRL_PRNG_RESET               7  /* NOT USED */
  #define SQLITE_TESTCTRL_BITVEC_TEST              8
  #define SQLITE_TESTCTRL_FAULT_INSTALL            9
  #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
  #define SQLITE_TESTCTRL_PENDING_BYTE            11
  #define SQLITE_TESTCTRL_ASSERT                  12
  #define SQLITE_TESTCTRL_ALWAYS                  13
  #define SQLITE_TESTCTRL_RESERVE                 14  /* NOT USED */
  #define SQLITE_TESTCTRL_OPTIMIZATIONS           15
  #define SQLITE_TESTCTRL_ISKEYWORD               16  /* NOT USED */
  #define SQLITE_TESTCTRL_SCRATCHMALLOC           17  /* NOT USED */
  #define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS      17
  #define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
  #define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
  #define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD    19
  #define SQLITE_TESTCTRL_NEVER_CORRUPT           20
  #define SQLITE_TESTCTRL_VDBE_COVERAGE           21
  #define SQLITE_TESTCTRL_BYTEORDER               22
  #define SQLITE_TESTCTRL_ISINIT                  23
  #define SQLITE_TESTCTRL_SORTER_MMAP             24
  #define SQLITE_TESTCTRL_IMPOSTER                25
  #define SQLITE_TESTCTRL_PARSER_COVERAGE         26
  #define SQLITE_TESTCTRL_RESULT_INTREAL          27
  #define SQLITE_TESTCTRL_PRNG_SEED               28
  #define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS     29
  #define SQLITE_TESTCTRL_SEEK_COUNT              30
  #define SQLITE_TESTCTRL_LAST                    30  /* Largest TESTCTRL */
  
  /*
  ** CAPI3REF: SQL Keyword Checking
  **
  ** These routines provide access to the set of SQL language keywords
  ** recognized by SQLite.  Applications can uses these routines to determine
  ** whether or not a specific identifier needs to be escaped (for example,
  ** by enclosing in double-quotes) so as not to confuse the parser.
  **
  ** The sqlite3_keyword_count() interface returns the number of distinct
  ** keywords understood by SQLite.
  **
  ** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and
  ** makes *Z point to that keyword expressed as UTF8 and writes the number
  ** of bytes in the keyword into *L.  The string that *Z points to is not
  ** zero-terminated.  The sqlite3_keyword_name(N,Z,L) routine returns
  ** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
  ** or L are NULL or invalid pointers then calls to
  ** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
  **
  ** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
  ** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
  ** if it is and zero if not.
  **
  ** The parser used by SQLite is forgiving.  It is often possible to use
  ** a keyword as an identifier as long as such use does not result in a
  ** parsing ambiguity.  For example, the statement
  ** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
  ** creates a new table named "BEGIN" with three columns named
  ** "REPLACE", "PRAGMA", and "END".  Nevertheless, best practice is to avoid
  ** using keywords as identifiers.  Common techniques used to avoid keyword
  ** name collisions include:
  ** <ul>
  ** <li> Put all identifier names inside double-quotes.  This is the official
  **      SQL way to escape identifier names.
  ** <li> Put identifier names inside &#91;...&#93;.  This is not standard SQL,
  **      but it is what SQL Server does and so lots of programmers use this
  **      technique.
  ** <li> Begin every identifier with the letter "Z" as no SQL keywords start
  **      with "Z".
  ** <li> Include a digit somewhere in every identifier name.
  ** </ul>
  **
  ** Note that the number of keywords understood by SQLite can depend on
  ** compile-time options.  For example, "VACUUM" is not a keyword if
  ** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option.  Also,
  ** new keywords may be added to future releases of SQLite.
  */
  SQLITE_API int sqlite3_keyword_count(void);
  SQLITE_API int sqlite3_keyword_name(int,const char**,int*);
  SQLITE_API int sqlite3_keyword_check(const char*,int);
  
  /*
  ** CAPI3REF: Dynamic String Object
  ** KEYWORDS: {dynamic string}
  **
  ** An instance of the sqlite3_str object contains a dynamically-sized
  ** string under construction.
  **
  ** The lifecycle of an sqlite3_str object is as follows:
  ** <ol>
  ** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
  ** <li> ^Text is appended to the sqlite3_str object using various
  ** methods, such as [sqlite3_str_appendf()].
  ** <li> ^The sqlite3_str object is destroyed and the string it created
  ** is returned using the [sqlite3_str_finish()] interface.
  ** </ol>
  */
  typedef struct sqlite3_str sqlite3_str;
  
  /*
  ** CAPI3REF: Create A New Dynamic String Object
  ** CONSTRUCTOR: sqlite3_str
  **
  ** ^The [sqlite3_str_new(D)] interface allocates and initializes
  ** a new [sqlite3_str] object.  To avoid memory leaks, the object returned by
  ** [sqlite3_str_new()] must be freed by a subsequent call to
  ** [sqlite3_str_finish(X)].
  **
  ** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
  ** valid [sqlite3_str] object, though in the event of an out-of-memory
  ** error the returned object might be a special singleton that will
  ** silently reject new text, always return SQLITE_NOMEM from
  ** [sqlite3_str_errcode()], always return 0 for
  ** [sqlite3_str_length()], and always return NULL from
  ** [sqlite3_str_finish(X)].  It is always safe to use the value
  ** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
  ** to any of the other [sqlite3_str] methods.
  **
  ** The D parameter to [sqlite3_str_new(D)] may be NULL.  If the
  ** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
  ** length of the string contained in the [sqlite3_str] object will be
  ** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
  ** of [SQLITE_MAX_LENGTH].
  */
  SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3*);
  
  /*
  ** CAPI3REF: Finalize A Dynamic String
  ** DESTRUCTOR: sqlite3_str
  **
  ** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
  ** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
  ** that contains the constructed string.  The calling application should
  ** pass the returned value to [sqlite3_free()] to avoid a memory leak.
  ** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
  ** errors were encountered during construction of the string.  ^The
  ** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
  ** string in [sqlite3_str] object X is zero bytes long.
  */
  SQLITE_API char *sqlite3_str_finish(sqlite3_str*);
  
  /*
  ** CAPI3REF: Add Content To A Dynamic String
  ** METHOD: sqlite3_str
  **
  ** These interfaces add content to an sqlite3_str object previously obtained
  ** from [sqlite3_str_new()].
  **
  ** ^The [sqlite3_str_appendf(X,F,...)] and
  ** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
  ** functionality of SQLite to append formatted text onto the end of
  ** [sqlite3_str] object X.
  **
  ** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
  ** onto the end of the [sqlite3_str] object X.  N must be non-negative.
  ** S must contain at least N non-zero bytes of content.  To append a
  ** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
  ** method instead.
  **
  ** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
  ** zero-terminated string S onto the end of [sqlite3_str] object X.
  **
  ** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
  ** single-byte character C onto the end of [sqlite3_str] object X.
  ** ^This method can be used, for example, to add whitespace indentation.
  **
  ** ^The [sqlite3_str_reset(X)] method resets the string under construction
  ** inside [sqlite3_str] object X back to zero bytes in length.
  **
  ** These methods do not return a result code.  ^If an error occurs, that fact
  ** is recorded in the [sqlite3_str] object and can be recovered by a
  ** subsequent call to [sqlite3_str_errcode(X)].
  */
  SQLITE_API void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
  SQLITE_API void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
  SQLITE_API void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
  SQLITE_API void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
  SQLITE_API void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
  SQLITE_API void sqlite3_str_reset(sqlite3_str*);
  
  /*
  ** CAPI3REF: Status Of A Dynamic String
  ** METHOD: sqlite3_str
  **
  ** These interfaces return the current status of an [sqlite3_str] object.
  **
  ** ^If any prior errors have occurred while constructing the dynamic string
  ** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
  ** an appropriate error code.  ^The [sqlite3_str_errcode(X)] method returns
  ** [SQLITE_NOMEM] following any out-of-memory error, or
  ** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
  ** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
  **
  ** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
  ** of the dynamic string under construction in [sqlite3_str] object X.
  ** ^The length returned by [sqlite3_str_length(X)] does not include the
  ** zero-termination byte.
  **
  ** ^The [sqlite3_str_value(X)] method returns a pointer to the current
  ** content of the dynamic string under construction in X.  The value
  ** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
  ** and might be freed or altered by any subsequent method on the same
  ** [sqlite3_str] object.  Applications must not used the pointer returned
  ** [sqlite3_str_value(X)] after any subsequent method call on the same
  ** object.  ^Applications may change the content of the string returned
  ** by [sqlite3_str_value(X)] as long as they do not write into any bytes
  ** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
  ** write any byte after any subsequent sqlite3_str method call.
  */
  SQLITE_API int sqlite3_str_errcode(sqlite3_str*);
  SQLITE_API int sqlite3_str_length(sqlite3_str*);
  SQLITE_API char *sqlite3_str_value(sqlite3_str*);
  
  /*
  ** CAPI3REF: SQLite Runtime Status
  **
  ** ^These interfaces are used to retrieve runtime status information
  ** about the performance of SQLite, and optionally to reset various
  ** highwater marks.  ^The first argument is an integer code for
  ** the specific parameter to measure.  ^(Recognized integer codes
  ** are of the form [status parameters | SQLITE_STATUS_...].)^
  ** ^The current value of the parameter is returned into *pCurrent.
  ** ^The highest recorded value is returned in *pHighwater.  ^If the
  ** resetFlag is true, then the highest record value is reset after
  ** *pHighwater is written.  ^(Some parameters do not record the highest
  ** value.  For those parameters
  ** nothing is written into *pHighwater and the resetFlag is ignored.)^
  ** ^(Other parameters record only the highwater mark and not the current
  ** value.  For these latter parameters nothing is written into *pCurrent.)^
  **
  ** ^The sqlite3_status() and sqlite3_status64() routines return
  ** SQLITE_OK on success and a non-zero [error code] on failure.
  **
  ** If either the current value or the highwater mark is too large to
  ** be represented by a 32-bit integer, then the values returned by
  ** sqlite3_status() are undefined.
  **
  ** See also: [sqlite3_db_status()]
  */
  SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
  SQLITE_API int sqlite3_status64(
    int op,
    sqlite3_int64 *pCurrent,
    sqlite3_int64 *pHighwater,
    int resetFlag
  );
  
  
  /*
  ** CAPI3REF: Status Parameters
  ** KEYWORDS: {status parameters}
  **
  ** These integer constants designate various run-time status parameters
  ** that can be returned by [sqlite3_status()].
  **
  ** <dl>
  ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
  ** <dd>This parameter is the current amount of memory checked out
  ** using [sqlite3_malloc()], either directly or indirectly.  The
  ** figure includes calls made to [sqlite3_malloc()] by the application
  ** and internal memory usage by the SQLite library.  Auxiliary page-cache
  ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
  ** this parameter.  The amount returned is the sum of the allocation
  ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
  **
  ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
  ** <dd>This parameter records the largest memory allocation request
  ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
  ** internal equivalents).  Only the value returned in the
  ** *pHighwater parameter to [sqlite3_status()] is of interest.
  ** The value written into the *pCurrent parameter is undefined.</dd>)^
  **
  ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
  ** <dd>This parameter records the number of separate memory allocations
  ** currently checked out.</dd>)^
  **
  ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
  ** <dd>This parameter returns the number of pages used out of the
  ** [pagecache memory allocator] that was configured using
  ** [SQLITE_CONFIG_PAGECACHE].  The
  ** value returned is in pages, not in bytes.</dd>)^
  **
  ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
  ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
  ** <dd>This parameter returns the number of bytes of page cache
  ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
  ** buffer and where forced to overflow to [sqlite3_malloc()].  The
  ** returned value includes allocations that overflowed because they
  ** where too large (they were larger than the "sz" parameter to
  ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
  ** no space was left in the page cache.</dd>)^
  **
  ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
  ** <dd>This parameter records the largest memory allocation request
  ** handed to the [pagecache memory allocator].  Only the value returned in the
  ** *pHighwater parameter to [sqlite3_status()] is of interest.
  ** The value written into the *pCurrent parameter is undefined.</dd>)^
  **
  ** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
  ** <dd>No longer used.</dd>
  **
  ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
  ** <dd>No longer used.</dd>
  **
  ** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
  ** <dd>No longer used.</dd>
  **
  ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
  ** <dd>The *pHighwater parameter records the deepest parser stack.
  ** The *pCurrent value is undefined.  The *pHighwater value is only
  ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
  ** </dl>
  **
  ** New status parameters may be added from time to time.
  */
  #define SQLITE_STATUS_MEMORY_USED          0
  #define SQLITE_STATUS_PAGECACHE_USED       1
  #define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
  #define SQLITE_STATUS_SCRATCH_USED         3  /* NOT USED */
  #define SQLITE_STATUS_SCRATCH_OVERFLOW     4  /* NOT USED */
  #define SQLITE_STATUS_MALLOC_SIZE          5
  #define SQLITE_STATUS_PARSER_STACK         6
  #define SQLITE_STATUS_PAGECACHE_SIZE       7
  #define SQLITE_STATUS_SCRATCH_SIZE         8  /* NOT USED */
  #define SQLITE_STATUS_MALLOC_COUNT         9
  
  /*
  ** CAPI3REF: Database Connection Status
  ** METHOD: sqlite3
  **
  ** ^This interface is used to retrieve runtime status information
  ** about a single [database connection].  ^The first argument is the
  ** database connection object to be interrogated.  ^The second argument
  ** is an integer constant, taken from the set of
  ** [SQLITE_DBSTATUS options], that
  ** determines the parameter to interrogate.  The set of
  ** [SQLITE_DBSTATUS options] is likely
  ** to grow in future releases of SQLite.
  **
  ** ^The current value of the requested parameter is written into *pCur
  ** and the highest instantaneous value is written into *pHiwtr.  ^If
  ** the resetFlg is true, then the highest instantaneous value is
  ** reset back down to the current value.
  **
  ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
  ** non-zero [error code] on failure.
  **
  ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
  */
  SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
  
  /*
  ** CAPI3REF: Status Parameters for database connections
  ** KEYWORDS: {SQLITE_DBSTATUS options}
  **
  ** These constants are the available integer "verbs" that can be passed as
  ** the second argument to the [sqlite3_db_status()] interface.
  **
  ** New verbs may be added in future releases of SQLite. Existing verbs
  ** might be discontinued. Applications should check the return code from
  ** [sqlite3_db_status()] to make sure that the call worked.
  ** The [sqlite3_db_status()] interface will return a non-zero error code
  ** if a discontinued or unsupported verb is invoked.
  **
  ** <dl>
  ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
  ** <dd>This parameter returns the number of lookaside memory slots currently
  ** checked out.</dd>)^
  **
  ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
  ** <dd>This parameter returns the number of malloc attempts that were
  ** satisfied using lookaside memory. Only the high-water value is meaningful;
  ** the current value is always zero.)^
  **
  ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
  ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
  ** <dd>This parameter returns the number malloc attempts that might have
  ** been satisfied using lookaside memory but failed due to the amount of
  ** memory requested being larger than the lookaside slot size.
  ** Only the high-water value is meaningful;
  ** the current value is always zero.)^
  **
  ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
  ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
  ** <dd>This parameter returns the number malloc attempts that might have
  ** been satisfied using lookaside memory but failed due to all lookaside
  ** memory already being in use.
  ** Only the high-water value is meaningful;
  ** the current value is always zero.)^
  **
  ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
  ** <dd>This parameter returns the approximate number of bytes of heap
  ** memory used by all pager caches associated with the database connection.)^
  ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
  **
  ** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
  ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
  ** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
  ** pager cache is shared between two or more connections the bytes of heap
  ** memory used by that pager cache is divided evenly between the attached
  ** connections.)^  In other words, if none of the pager caches associated
  ** with the database connection are shared, this request returns the same
  ** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
  ** shared, the value returned by this call will be smaller than that returned
  ** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
  ** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
  **
  ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
  ** <dd>This parameter returns the approximate number of bytes of heap
  ** memory used to store the schema for all databases associated
  ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
  ** ^The full amount of memory used by the schemas is reported, even if the
  ** schema memory is shared with other database connections due to
  ** [shared cache mode] being enabled.
  ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
  **
  ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
  ** <dd>This parameter returns the approximate number of bytes of heap
  ** and lookaside memory used by all prepared statements associated with
  ** the database connection.)^
  ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
  ** </dd>
  **
  ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
  ** <dd>This parameter returns the number of pager cache hits that have
  ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
  ** is always 0.
  ** </dd>
  **
  ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
  ** <dd>This parameter returns the number of pager cache misses that have
  ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
  ** is always 0.
  ** </dd>
  **
  ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
  ** <dd>This parameter returns the number of dirty cache entries that have
  ** been written to disk. Specifically, the number of pages written to the
  ** wal file in wal mode databases, or the number of pages written to the
  ** database file in rollback mode databases. Any pages written as part of
  ** transaction rollback or database recovery operations are not included.
  ** If an IO or other error occurs while writing a page to disk, the effect
  ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
  ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
  ** </dd>
  **
  ** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
  ** <dd>This parameter returns the number of dirty cache entries that have
  ** been written to disk in the middle of a transaction due to the page
  ** cache overflowing. Transactions are more efficient if they are written
  ** to disk all at once. When pages spill mid-transaction, that introduces
  ** additional overhead. This parameter can be used help identify
  ** inefficiencies that can be resolved by increasing the cache size.
  ** </dd>
  **
  ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
  ** <dd>This parameter returns zero for the current value if and only if
  ** all foreign key constraints (deferred or immediate) have been
  ** resolved.)^  ^The highwater mark is always 0.
  ** </dd>
  ** </dl>
  */
  #define SQLITE_DBSTATUS_LOOKASIDE_USED       0
  #define SQLITE_DBSTATUS_CACHE_USED           1
  #define SQLITE_DBSTATUS_SCHEMA_USED          2
  #define SQLITE_DBSTATUS_STMT_USED            3
  #define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
  #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
  #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
  #define SQLITE_DBSTATUS_CACHE_HIT            7
  #define SQLITE_DBSTATUS_CACHE_MISS           8
  #define SQLITE_DBSTATUS_CACHE_WRITE          9
  #define SQLITE_DBSTATUS_DEFERRED_FKS        10
  #define SQLITE_DBSTATUS_CACHE_USED_SHARED   11
  #define SQLITE_DBSTATUS_CACHE_SPILL         12
  #define SQLITE_DBSTATUS_MAX                 12   /* Largest defined DBSTATUS */
  
  
  /*
  ** CAPI3REF: Prepared Statement Status
  ** METHOD: sqlite3_stmt
  **
  ** ^(Each prepared statement maintains various
  ** [SQLITE_STMTSTATUS counters] that measure the number
  ** of times it has performed specific operations.)^  These counters can
  ** be used to monitor the performance characteristics of the prepared
  ** statements.  For example, if the number of table steps greatly exceeds
  ** the number of table searches or result rows, that would tend to indicate
  ** that the prepared statement is using a full table scan rather than
  ** an index.
  **
  ** ^(This interface is used to retrieve and reset counter values from
  ** a [prepared statement].  The first argument is the prepared statement
  ** object to be interrogated.  The second argument
  ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
  ** to be interrogated.)^
  ** ^The current value of the requested counter is returned.
  ** ^If the resetFlg is true, then the counter is reset to zero after this
  ** interface call returns.
  **
  ** See also: [sqlite3_status()] and [sqlite3_db_status()].
  */
  SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
  
  /*
  ** CAPI3REF: Status Parameters for prepared statements
  ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
  **
  ** These preprocessor macros define integer codes that name counter
  ** values associated with the [sqlite3_stmt_status()] interface.
  ** The meanings of the various counters are as follows:
  **
  ** <dl>
  ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
  ** <dd>^This is the number of times that SQLite has stepped forward in
  ** a table as part of a full table scan.  Large numbers for this counter
  ** may indicate opportunities for performance improvement through
  ** careful use of indices.</dd>
  **
  ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
  ** <dd>^This is the number of sort operations that have occurred.
  ** A non-zero value in this counter may indicate an opportunity to
  ** improvement performance through careful use of indices.</dd>
  **
  ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
  ** <dd>^This is the number of rows inserted into transient indices that
  ** were created automatically in order to help joins run faster.
  ** A non-zero value in this counter may indicate an opportunity to
  ** improvement performance by adding permanent indices that do not
  ** need to be reinitialized each time the statement is run.</dd>
  **
  ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
  ** <dd>^This is the number of virtual machine operations executed
  ** by the prepared statement if that number is less than or equal
  ** to 2147483647.  The number of virtual machine operations can be
  ** used as a proxy for the total work done by the prepared statement.
  ** If the number of virtual machine operations exceeds 2147483647
  ** then the value returned by this statement status code is undefined.
  **
  ** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
  ** <dd>^This is the number of times that the prepare statement has been
  ** automatically regenerated due to schema changes or changes to
  ** [bound parameters] that might affect the query plan.
  **
  ** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
  ** <dd>^This is the number of times that the prepared statement has
  ** been run.  A single "run" for the purposes of this counter is one
  ** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
  ** The counter is incremented on the first [sqlite3_step()] call of each
  ** cycle.
  **
  ** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
  ** <dd>^This is the approximate number of bytes of heap memory
  ** used to store the prepared statement.  ^This value is not actually
  ** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
  ** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
  ** </dd>
  ** </dl>
  */
  #define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
  #define SQLITE_STMTSTATUS_SORT              2
  #define SQLITE_STMTSTATUS_AUTOINDEX         3
  #define SQLITE_STMTSTATUS_VM_STEP           4
  #define SQLITE_STMTSTATUS_REPREPARE         5
  #define SQLITE_STMTSTATUS_RUN               6
  #define SQLITE_STMTSTATUS_MEMUSED           99
  
  /*
  ** CAPI3REF: Custom Page Cache Object
  **
  ** The sqlite3_pcache type is opaque.  It is implemented by
  ** the pluggable module.  The SQLite core has no knowledge of
  ** its size or internal structure and never deals with the
  ** sqlite3_pcache object except by holding and passing pointers
  ** to the object.
  **
  ** See [sqlite3_pcache_methods2] for additional information.
  */
  typedef struct sqlite3_pcache sqlite3_pcache;
  
  /*
  ** CAPI3REF: Custom Page Cache Object
  **
  ** The sqlite3_pcache_page object represents a single page in the
  ** page cache.  The page cache will allocate instances of this
  ** object.  Various methods of the page cache use pointers to instances
  ** of this object as parameters or as their return value.
  **
  ** See [sqlite3_pcache_methods2] for additional information.
  */
  typedef struct sqlite3_pcache_page sqlite3_pcache_page;
  struct sqlite3_pcache_page {
    void *pBuf;        /* The content of the page */
    void *pExtra;      /* Extra information associated with the page */
  };
  
  /*
  ** CAPI3REF: Application Defined Page Cache.
  ** KEYWORDS: {page cache}
  **
  ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
  ** register an alternative page cache implementation by passing in an
  ** instance of the sqlite3_pcache_methods2 structure.)^
  ** In many applications, most of the heap memory allocated by
  ** SQLite is used for the page cache.
  ** By implementing a
  ** custom page cache using this API, an application can better control
  ** the amount of memory consumed by SQLite, the way in which
  ** that memory is allocated and released, and the policies used to
  ** determine exactly which parts of a database file are cached and for
  ** how long.
  **
  ** The alternative page cache mechanism is an
  ** extreme measure that is only needed by the most demanding applications.
  ** The built-in page cache is recommended for most uses.
  **
  ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
  ** internal buffer by SQLite within the call to [sqlite3_config].  Hence
  ** the application may discard the parameter after the call to
  ** [sqlite3_config()] returns.)^
  **
  ** [[the xInit() page cache method]]
  ** ^(The xInit() method is called once for each effective
  ** call to [sqlite3_initialize()])^
  ** (usually only once during the lifetime of the process). ^(The xInit()
  ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
  ** The intent of the xInit() method is to set up global data structures
  ** required by the custom page cache implementation.
  ** ^(If the xInit() method is NULL, then the
  ** built-in default page cache is used instead of the application defined
  ** page cache.)^
  **
  ** [[the xShutdown() page cache method]]
  ** ^The xShutdown() method is called by [sqlite3_shutdown()].
  ** It can be used to clean up
  ** any outstanding resources before process shutdown, if required.
  ** ^The xShutdown() method may be NULL.
  **
  ** ^SQLite automatically serializes calls to the xInit method,
  ** so the xInit method need not be threadsafe.  ^The
  ** xShutdown method is only called from [sqlite3_shutdown()] so it does
  ** not need to be threadsafe either.  All other methods must be threadsafe
  ** in multithreaded applications.
  **
  ** ^SQLite will never invoke xInit() more than once without an intervening
  ** call to xShutdown().
  **
  ** [[the xCreate() page cache methods]]
  ** ^SQLite invokes the xCreate() method to construct a new cache instance.
  ** SQLite will typically create one cache instance for each open database file,
  ** though this is not guaranteed. ^The
  ** first parameter, szPage, is the size in bytes of the pages that must
  ** be allocated by the cache.  ^szPage will always a power of two.  ^The
  ** second parameter szExtra is a number of bytes of extra storage
  ** associated with each page cache entry.  ^The szExtra parameter will
  ** a number less than 250.  SQLite will use the
  ** extra szExtra bytes on each page to store metadata about the underlying
  ** database page on disk.  The value passed into szExtra depends
  ** on the SQLite version, the target platform, and how SQLite was compiled.
  ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
  ** created will be used to cache database pages of a file stored on disk, or
  ** false if it is used for an in-memory database. The cache implementation
  ** does not have to do anything special based with the value of bPurgeable;
  ** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
  ** never invoke xUnpin() except to deliberately delete a page.
  ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
  ** false will always have the "discard" flag set to true.
  ** ^Hence, a cache created with bPurgeable false will
  ** never contain any unpinned pages.
  **
  ** [[the xCachesize() page cache method]]
  ** ^(The xCachesize() method may be called at any time by SQLite to set the
  ** suggested maximum cache-size (number of pages stored by) the cache
  ** instance passed as the first argument. This is the value configured using
  ** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
  ** parameter, the implementation is not required to do anything with this
  ** value; it is advisory only.
  **
  ** [[the xPagecount() page cache methods]]
  ** The xPagecount() method must return the number of pages currently
  ** stored in the cache, both pinned and unpinned.
  **
  ** [[the xFetch() page cache methods]]
  ** The xFetch() method locates a page in the cache and returns a pointer to
  ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
  ** The pBuf element of the returned sqlite3_pcache_page object will be a
  ** pointer to a buffer of szPage bytes used to store the content of a
  ** single database page.  The pExtra element of sqlite3_pcache_page will be
  ** a pointer to the szExtra bytes of extra storage that SQLite has requested
  ** for each entry in the page cache.
  **
  ** The page to be fetched is determined by the key. ^The minimum key value
  ** is 1.  After it has been retrieved using xFetch, the page is considered
  ** to be "pinned".
  **
  ** If the requested page is already in the page cache, then the page cache
  ** implementation must return a pointer to the page buffer with its content
  ** intact.  If the requested page is not already in the cache, then the
  ** cache implementation should use the value of the createFlag
  ** parameter to help it determined what action to take:
  **
  ** <table border=1 width=85% align=center>
  ** <tr><th> createFlag <th> Behavior when page is not already in cache
  ** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
  ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
  **                 Otherwise return NULL.
  ** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
  **                 NULL if allocating a new page is effectively impossible.
  ** </table>
  **
  ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
  ** will only use a createFlag of 2 after a prior call with a createFlag of 1
  ** failed.)^  In between the xFetch() calls, SQLite may
  ** attempt to unpin one or more cache pages by spilling the content of
  ** pinned pages to disk and synching the operating system disk cache.
  **
  ** [[the xUnpin() page cache method]]
  ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
  ** as its second argument.  If the third parameter, discard, is non-zero,
  ** then the page must be evicted from the cache.
  ** ^If the discard parameter is
  ** zero, then the page may be discarded or retained at the discretion of
  ** page cache implementation. ^The page cache implementation
  ** may choose to evict unpinned pages at any time.
  **
  ** The cache must not perform any reference counting. A single
  ** call to xUnpin() unpins the page regardless of the number of prior calls
  ** to xFetch().
  **
  ** [[the xRekey() page cache methods]]
  ** The xRekey() method is used to change the key value associated with the
  ** page passed as the second argument. If the cache
  ** previously contains an entry associated with newKey, it must be
  ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
  ** to be pinned.
  **
  ** When SQLite calls the xTruncate() method, the cache must discard all
  ** existing cache entries with page numbers (keys) greater than or equal
  ** to the value of the iLimit parameter passed to xTruncate(). If any
  ** of these pages are pinned, they are implicitly unpinned, meaning that
  ** they can be safely discarded.
  **
  ** [[the xDestroy() page cache method]]
  ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
  ** All resources associated with the specified cache should be freed. ^After
  ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
  ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
  ** functions.
  **
  ** [[the xShrink() page cache method]]
  ** ^SQLite invokes the xShrink() method when it wants the page cache to
  ** free up as much of heap memory as possible.  The page cache implementation
  ** is not obligated to free any memory, but well-behaved implementations should
  ** do their best.
  */
  typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
  struct sqlite3_pcache_methods2 {
    int iVersion;
    void *pArg;
    int (*xInit)(void*);
    void (*xShutdown)(void*);
    sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
    void (*xCachesize)(sqlite3_pcache*, int nCachesize);
    int (*xPagecount)(sqlite3_pcache*);
    sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
    void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
    void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
        unsigned oldKey, unsigned newKey);
    void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
    void (*xDestroy)(sqlite3_pcache*);
    void (*xShrink)(sqlite3_pcache*);
  };
  
  /*
  ** This is the obsolete pcache_methods object that has now been replaced
  ** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
  ** retained in the header file for backwards compatibility only.
  */
  typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
  struct sqlite3_pcache_methods {
    void *pArg;
    int (*xInit)(void*);
    void (*xShutdown)(void*);
    sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
    void (*xCachesize)(sqlite3_pcache*, int nCachesize);
    int (*xPagecount)(sqlite3_pcache*);
    void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
    void (*xUnpin)(sqlite3_pcache*, void*, int discard);
    void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
    void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
    void (*xDestroy)(sqlite3_pcache*);
  };
  
  
  /*
  ** CAPI3REF: Online Backup Object
  **
  ** The sqlite3_backup object records state information about an ongoing
  ** online backup operation.  ^The sqlite3_backup object is created by
  ** a call to [sqlite3_backup_init()] and is destroyed by a call to
  ** [sqlite3_backup_finish()].
  **
  ** See Also: [Using the SQLite Online Backup API]
  */
  typedef struct sqlite3_backup sqlite3_backup;
  
  /*
  ** CAPI3REF: Online Backup API.
  **
  ** The backup API copies the content of one database into another.
  ** It is useful either for creating backups of databases or
  ** for copying in-memory databases to or from persistent files.
  **
  ** See Also: [Using the SQLite Online Backup API]
  **
  ** ^SQLite holds a write transaction open on the destination database file
  ** for the duration of the backup operation.
  ** ^The source database is read-locked only while it is being read;
  ** it is not locked continuously for the entire backup operation.
  ** ^Thus, the backup may be performed on a live source database without
  ** preventing other database connections from
  ** reading or writing to the source database while the backup is underway.
  **
  ** ^(To perform a backup operation:
  **   <ol>
  **     <li><b>sqlite3_backup_init()</b> is called once to initialize the
  **         backup,
  **     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
  **         the data between the two databases, and finally
  **     <li><b>sqlite3_backup_finish()</b> is called to release all resources
  **         associated with the backup operation.
  **   </ol>)^
  ** There should be exactly one call to sqlite3_backup_finish() for each
  ** successful call to sqlite3_backup_init().
  **
  ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
  **
  ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
  ** [database connection] associated with the destination database
  ** and the database name, respectively.
  ** ^The database name is "main" for the main database, "temp" for the
  ** temporary database, or the name specified after the AS keyword in
  ** an [ATTACH] statement for an attached database.
  ** ^The S and M arguments passed to
  ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
  ** and database name of the source database, respectively.
  ** ^The source and destination [database connections] (parameters S and D)
  ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
  ** an error.
  **
  ** ^A call to sqlite3_backup_init() will fail, returning NULL, if
  ** there is already a read or read-write transaction open on the
  ** destination database.
  **
  ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
  ** returned and an error code and error message are stored in the
  ** destination [database connection] D.
  ** ^The error code and message for the failed call to sqlite3_backup_init()
  ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
  ** [sqlite3_errmsg16()] functions.
  ** ^A successful call to sqlite3_backup_init() returns a pointer to an
  ** [sqlite3_backup] object.
  ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
  ** sqlite3_backup_finish() functions to perform the specified backup
  ** operation.
  **
  ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
  **
  ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
  ** the source and destination databases specified by [sqlite3_backup] object B.
  ** ^If N is negative, all remaining source pages are copied.
  ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
  ** are still more pages to be copied, then the function returns [SQLITE_OK].
  ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
  ** from source to destination, then it returns [SQLITE_DONE].
  ** ^If an error occurs while running sqlite3_backup_step(B,N),
  ** then an [error code] is returned. ^As well as [SQLITE_OK] and
  ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
  ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
  ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
  **
  ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
  ** <ol>
  ** <li> the destination database was opened read-only, or
  ** <li> the destination database is using write-ahead-log journaling
  ** and the destination and source page sizes differ, or
  ** <li> the destination database is an in-memory database and the
  ** destination and source page sizes differ.
  ** </ol>)^
  **
  ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
  ** the [sqlite3_busy_handler | busy-handler function]
  ** is invoked (if one is specified). ^If the
  ** busy-handler returns non-zero before the lock is available, then
  ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
  ** sqlite3_backup_step() can be retried later. ^If the source
  ** [database connection]
  ** is being used to write to the source database when sqlite3_backup_step()
  ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
  ** case the call to sqlite3_backup_step() can be retried later on. ^(If
  ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
  ** [SQLITE_READONLY] is returned, then
  ** there is no point in retrying the call to sqlite3_backup_step(). These
  ** errors are considered fatal.)^  The application must accept
  ** that the backup operation has failed and pass the backup operation handle
  ** to the sqlite3_backup_finish() to release associated resources.
  **
  ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
  ** on the destination file. ^The exclusive lock is not released until either
  ** sqlite3_backup_finish() is called or the backup operation is complete
  ** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
  ** sqlite3_backup_step() obtains a [shared lock] on the source database that
  ** lasts for the duration of the sqlite3_backup_step() call.
  ** ^Because the source database is not locked between calls to
  ** sqlite3_backup_step(), the source database may be modified mid-way
  ** through the backup process.  ^If the source database is modified by an
  ** external process or via a database connection other than the one being
  ** used by the backup operation, then the backup will be automatically
  ** restarted by the next call to sqlite3_backup_step(). ^If the source
  ** database is modified by the using the same database connection as is used
  ** by the backup operation, then the backup database is automatically
  ** updated at the same time.
  **
  ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
  **
  ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
  ** application wishes to abandon the backup operation, the application
  ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
  ** ^The sqlite3_backup_finish() interfaces releases all
  ** resources associated with the [sqlite3_backup] object.
  ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
  ** active write-transaction on the destination database is rolled back.
  ** The [sqlite3_backup] object is invalid
  ** and may not be used following a call to sqlite3_backup_finish().
  **
  ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
  ** sqlite3_backup_step() errors occurred, regardless or whether or not
  ** sqlite3_backup_step() completed.
  ** ^If an out-of-memory condition or IO error occurred during any prior
  ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
  ** sqlite3_backup_finish() returns the corresponding [error code].
  **
  ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
  ** is not a permanent error and does not affect the return value of
  ** sqlite3_backup_finish().
  **
  ** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
  ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
  **
  ** ^The sqlite3_backup_remaining() routine returns the number of pages still
  ** to be backed up at the conclusion of the most recent sqlite3_backup_step().
  ** ^The sqlite3_backup_pagecount() routine returns the total number of pages
  ** in the source database at the conclusion of the most recent
  ** sqlite3_backup_step().
  ** ^(The values returned by these functions are only updated by
  ** sqlite3_backup_step(). If the source database is modified in a way that
  ** changes the size of the source database or the number of pages remaining,
  ** those changes are not reflected in the output of sqlite3_backup_pagecount()
  ** and sqlite3_backup_remaining() until after the next
  ** sqlite3_backup_step().)^
  **
  ** <b>Concurrent Usage of Database Handles</b>
  **
  ** ^The source [database connection] may be used by the application for other
  ** purposes while a backup operation is underway or being initialized.
  ** ^If SQLite is compiled and configured to support threadsafe database
  ** connections, then the source database connection may be used concurrently
  ** from within other threads.
  **
  ** However, the application must guarantee that the destination
  ** [database connection] is not passed to any other API (by any thread) after
  ** sqlite3_backup_init() is called and before the corresponding call to
  ** sqlite3_backup_finish().  SQLite does not currently check to see
  ** if the application incorrectly accesses the destination [database connection]
  ** and so no error code is reported, but the operations may malfunction
  ** nevertheless.  Use of the destination database connection while a
  ** backup is in progress might also also cause a mutex deadlock.
  **
  ** If running in [shared cache mode], the application must
  ** guarantee that the shared cache used by the destination database
  ** is not accessed while the backup is running. In practice this means
  ** that the application must guarantee that the disk file being
  ** backed up to is not accessed by any connection within the process,
  ** not just the specific connection that was passed to sqlite3_backup_init().
  **
  ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
  ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
  ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
  ** APIs are not strictly speaking threadsafe. If they are invoked at the
  ** same time as another thread is invoking sqlite3_backup_step() it is
  ** possible that they return invalid values.
  */
  SQLITE_API sqlite3_backup *sqlite3_backup_init(
    sqlite3 *pDest,                        /* Destination database handle */
    const char *zDestName,                 /* Destination database name */
    sqlite3 *pSource,                      /* Source database handle */
    const char *zSourceName                /* Source database name */
  );
  SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
  SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
  SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
  SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
  
  /*
  ** CAPI3REF: Unlock Notification
  ** METHOD: sqlite3
  **
  ** ^When running in shared-cache mode, a database operation may fail with
  ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
  ** individual tables within the shared-cache cannot be obtained. See
  ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
  ** ^This API may be used to register a callback that SQLite will invoke
  ** when the connection currently holding the required lock relinquishes it.
  ** ^This API is only available if the library was compiled with the
  ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
  **
  ** See Also: [Using the SQLite Unlock Notification Feature].
  **
  ** ^Shared-cache locks are released when a database connection concludes
  ** its current transaction, either by committing it or rolling it back.
  **
  ** ^When a connection (known as the blocked connection) fails to obtain a
  ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
  ** identity of the database connection (the blocking connection) that
  ** has locked the required resource is stored internally. ^After an
  ** application receives an SQLITE_LOCKED error, it may call the
  ** sqlite3_unlock_notify() method with the blocked connection handle as
  ** the first argument to register for a callback that will be invoked
  ** when the blocking connections current transaction is concluded. ^The
  ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
  ** call that concludes the blocking connection's transaction.
  **
  ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
  ** there is a chance that the blocking connection will have already
  ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
  ** If this happens, then the specified callback is invoked immediately,
  ** from within the call to sqlite3_unlock_notify().)^
  **
  ** ^If the blocked connection is attempting to obtain a write-lock on a
  ** shared-cache table, and more than one other connection currently holds
  ** a read-lock on the same table, then SQLite arbitrarily selects one of
  ** the other connections to use as the blocking connection.
  **
  ** ^(There may be at most one unlock-notify callback registered by a
  ** blocked connection. If sqlite3_unlock_notify() is called when the
  ** blocked connection already has a registered unlock-notify callback,
  ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
  ** called with a NULL pointer as its second argument, then any existing
  ** unlock-notify callback is canceled. ^The blocked connections
  ** unlock-notify callback may also be canceled by closing the blocked
  ** connection using [sqlite3_close()].
  **
  ** The unlock-notify callback is not reentrant. If an application invokes
  ** any sqlite3_xxx API functions from within an unlock-notify callback, a
  ** crash or deadlock may be the result.
  **
  ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
  ** returns SQLITE_OK.
  **
  ** <b>Callback Invocation Details</b>
  **
  ** When an unlock-notify callback is registered, the application provides a
  ** single void* pointer that is passed to the callback when it is invoked.
  ** However, the signature of the callback function allows SQLite to pass
  ** it an array of void* context pointers. The first argument passed to
  ** an unlock-notify callback is a pointer to an array of void* pointers,
  ** and the second is the number of entries in the array.
  **
  ** When a blocking connection's transaction is concluded, there may be
  ** more than one blocked connection that has registered for an unlock-notify
  ** callback. ^If two or more such blocked connections have specified the
  ** same callback function, then instead of invoking the callback function
  ** multiple times, it is invoked once with the set of void* context pointers
  ** specified by the blocked connections bundled together into an array.
  ** This gives the application an opportunity to prioritize any actions
  ** related to the set of unblocked database connections.
  **
  ** <b>Deadlock Detection</b>
  **
  ** Assuming that after registering for an unlock-notify callback a
  ** database waits for the callback to be issued before taking any further
  ** action (a reasonable assumption), then using this API may cause the
  ** application to deadlock. For example, if connection X is waiting for
  ** connection Y's transaction to be concluded, and similarly connection
  ** Y is waiting on connection X's transaction, then neither connection
  ** will proceed and the system may remain deadlocked indefinitely.
  **
  ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
  ** detection. ^If a given call to sqlite3_unlock_notify() would put the
  ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
  ** unlock-notify callback is registered. The system is said to be in
  ** a deadlocked state if connection A has registered for an unlock-notify
  ** callback on the conclusion of connection B's transaction, and connection
  ** B has itself registered for an unlock-notify callback when connection
  ** A's transaction is concluded. ^Indirect deadlock is also detected, so
  ** the system is also considered to be deadlocked if connection B has
  ** registered for an unlock-notify callback on the conclusion of connection
  ** C's transaction, where connection C is waiting on connection A. ^Any
  ** number of levels of indirection are allowed.
  **
  ** <b>The "DROP TABLE" Exception</b>
  **
  ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
  ** always appropriate to call sqlite3_unlock_notify(). There is however,
  ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
  ** SQLite checks if there are any currently executing SELECT statements
  ** that belong to the same connection. If there are, SQLITE_LOCKED is
  ** returned. In this case there is no "blocking connection", so invoking
  ** sqlite3_unlock_notify() results in the unlock-notify callback being
  ** invoked immediately. If the application then re-attempts the "DROP TABLE"
  ** or "DROP INDEX" query, an infinite loop might be the result.
  **
  ** One way around this problem is to check the extended error code returned
  ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
  ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
  ** the special "DROP TABLE/INDEX" case, the extended error code is just
  ** SQLITE_LOCKED.)^
  */
  SQLITE_API int sqlite3_unlock_notify(
    sqlite3 *pBlocked,                          /* Waiting connection */
    void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
    void *pNotifyArg                            /* Argument to pass to xNotify */
  );
  
  
  /*
  ** CAPI3REF: String Comparison
  **
  ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
  ** and extensions to compare the contents of two buffers containing UTF-8
  ** strings in a case-independent fashion, using the same definition of "case
  ** independence" that SQLite uses internally when comparing identifiers.
  */
  SQLITE_API int sqlite3_stricmp(const char *, const char *);
  SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
  
  /*
  ** CAPI3REF: String Globbing
  *
  ** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
  ** string X matches the [GLOB] pattern P.
  ** ^The definition of [GLOB] pattern matching used in
  ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
  ** SQL dialect understood by SQLite.  ^The [sqlite3_strglob(P,X)] function
  ** is case sensitive.
  **
  ** Note that this routine returns zero on a match and non-zero if the strings
  ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
  **
  ** See also: [sqlite3_strlike()].
  */
  SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
  
  /*
  ** CAPI3REF: String LIKE Matching
  *
  ** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
  ** string X matches the [LIKE] pattern P with escape character E.
  ** ^The definition of [LIKE] pattern matching used in
  ** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
  ** operator in the SQL dialect understood by SQLite.  ^For "X LIKE P" without
  ** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
  ** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
  ** insensitive - equivalent upper and lower case ASCII characters match
  ** one another.
  **
  ** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
  ** only ASCII characters are case folded.
  **
  ** Note that this routine returns zero on a match and non-zero if the strings
  ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
  **
  ** See also: [sqlite3_strglob()].
  */
  SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
  
  /*
  ** CAPI3REF: Error Logging Interface
  **
  ** ^The [sqlite3_log()] interface writes a message into the [error log]
  ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
  ** ^If logging is enabled, the zFormat string and subsequent arguments are
  ** used with [sqlite3_snprintf()] to generate the final output string.
  **
  ** The sqlite3_log() interface is intended for use by extensions such as
  ** virtual tables, collating functions, and SQL functions.  While there is
  ** nothing to prevent an application from calling sqlite3_log(), doing so
  ** is considered bad form.
  **
  ** The zFormat string must not be NULL.
  **
  ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
  ** will not use dynamically allocated memory.  The log message is stored in
  ** a fixed-length buffer on the stack.  If the log message is longer than
  ** a few hundred characters, it will be truncated to the length of the
  ** buffer.
  */
  SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
  
  /*
  ** CAPI3REF: Write-Ahead Log Commit Hook
  ** METHOD: sqlite3
  **
  ** ^The [sqlite3_wal_hook()] function is used to register a callback that
  ** is invoked each time data is committed to a database in wal mode.
  **
  ** ^(The callback is invoked by SQLite after the commit has taken place and
  ** the associated write-lock on the database released)^, so the implementation
  ** may read, write or [checkpoint] the database as required.
  **
  ** ^The first parameter passed to the callback function when it is invoked
  ** is a copy of the third parameter passed to sqlite3_wal_hook() when
  ** registering the callback. ^The second is a copy of the database handle.
  ** ^The third parameter is the name of the database that was written to -
  ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
  ** is the number of pages currently in the write-ahead log file,
  ** including those that were just committed.
  **
  ** The callback function should normally return [SQLITE_OK].  ^If an error
  ** code is returned, that error will propagate back up through the
  ** SQLite code base to cause the statement that provoked the callback
  ** to report an error, though the commit will have still occurred. If the
  ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
  ** that does not correspond to any valid SQLite error code, the results
  ** are undefined.
  **
  ** A single database handle may have at most a single write-ahead log callback
  ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
  ** previously registered write-ahead log callback. ^Note that the
  ** [sqlite3_wal_autocheckpoint()] interface and the
  ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
  ** overwrite any prior [sqlite3_wal_hook()] settings.
  */
  SQLITE_API void *sqlite3_wal_hook(
    sqlite3*,
    int(*)(void *,sqlite3*,const char*,int),
    void*
  );
  
  /*
  ** CAPI3REF: Configure an auto-checkpoint
  ** METHOD: sqlite3
  **
  ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
  ** [sqlite3_wal_hook()] that causes any database on [database connection] D
  ** to automatically [checkpoint]
  ** after committing a transaction if there are N or
  ** more frames in the [write-ahead log] file.  ^Passing zero or
  ** a negative value as the nFrame parameter disables automatic
  ** checkpoints entirely.
  **
  ** ^The callback registered by this function replaces any existing callback
  ** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
  ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
  ** configured by this function.
  **
  ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
  ** from SQL.
  **
  ** ^Checkpoints initiated by this mechanism are
  ** [sqlite3_wal_checkpoint_v2|PASSIVE].
  **
  ** ^Every new [database connection] defaults to having the auto-checkpoint
  ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
  ** pages.  The use of this interface
  ** is only necessary if the default setting is found to be suboptimal
  ** for a particular application.
  */
  SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
  
  /*
  ** CAPI3REF: Checkpoint a database
  ** METHOD: sqlite3
  **
  ** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
  ** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
  **
  ** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
  ** [write-ahead log] for database X on [database connection] D to be
  ** transferred into the database file and for the write-ahead log to
  ** be reset.  See the [checkpointing] documentation for addition
  ** information.
  **
  ** This interface used to be the only way to cause a checkpoint to
  ** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
  ** interface was added.  This interface is retained for backwards
  ** compatibility and as a convenience for applications that need to manually
  ** start a callback but which do not need the full power (and corresponding
  ** complication) of [sqlite3_wal_checkpoint_v2()].
  */
  SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
  
  /*
  ** CAPI3REF: Checkpoint a database
  ** METHOD: sqlite3
  **
  ** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
  ** operation on database X of [database connection] D in mode M.  Status
  ** information is written back into integers pointed to by L and C.)^
  ** ^(The M parameter must be a valid [checkpoint mode]:)^
  **
  ** <dl>
  ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
  **   ^Checkpoint as many frames as possible without waiting for any database
  **   readers or writers to finish, then sync the database file if all frames
  **   in the log were checkpointed. ^The [busy-handler callback]
  **   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
  **   ^On the other hand, passive mode might leave the checkpoint unfinished
  **   if there are concurrent readers or writers.
  **
  ** <dt>SQLITE_CHECKPOINT_FULL<dd>
  **   ^This mode blocks (it invokes the
  **   [sqlite3_busy_handler|busy-handler callback]) until there is no
  **   database writer and all readers are reading from the most recent database
  **   snapshot. ^It then checkpoints all frames in the log file and syncs the
  **   database file. ^This mode blocks new database writers while it is pending,
  **   but new database readers are allowed to continue unimpeded.
  **
  ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
  **   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
  **   that after checkpointing the log file it blocks (calls the
  **   [busy-handler callback])
  **   until all readers are reading from the database file only. ^This ensures
  **   that the next writer will restart the log file from the beginning.
  **   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
  **   database writer attempts while it is pending, but does not impede readers.
  **
  ** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
  **   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
  **   addition that it also truncates the log file to zero bytes just prior
  **   to a successful return.
  ** </dl>
  **
  ** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
  ** the log file or to -1 if the checkpoint could not run because
  ** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
  ** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
  ** log file (including any that were already checkpointed before the function
  ** was called) or to -1 if the checkpoint could not run due to an error or
  ** because the database is not in WAL mode. ^Note that upon successful
  ** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
  ** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
  **
  ** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
  ** any other process is running a checkpoint operation at the same time, the
  ** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
  ** busy-handler configured, it will not be invoked in this case.
  **
  ** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
  ** exclusive "writer" lock on the database file. ^If the writer lock cannot be
  ** obtained immediately, and a busy-handler is configured, it is invoked and
  ** the writer lock retried until either the busy-handler returns 0 or the lock
  ** is successfully obtained. ^The busy-handler is also invoked while waiting for
  ** database readers as described above. ^If the busy-handler returns 0 before
  ** the writer lock is obtained or while waiting for database readers, the
  ** checkpoint operation proceeds from that point in the same way as
  ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
  ** without blocking any further. ^SQLITE_BUSY is returned in this case.
  **
  ** ^If parameter zDb is NULL or points to a zero length string, then the
  ** specified operation is attempted on all WAL databases [attached] to
  ** [database connection] db.  In this case the
  ** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
  ** an SQLITE_BUSY error is encountered when processing one or more of the
  ** attached WAL databases, the operation is still attempted on any remaining
  ** attached databases and SQLITE_BUSY is returned at the end. ^If any other
  ** error occurs while processing an attached database, processing is abandoned
  ** and the error code is returned to the caller immediately. ^If no error
  ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
  ** databases, SQLITE_OK is returned.
  **
  ** ^If database zDb is the name of an attached database that is not in WAL
  ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
  ** zDb is not NULL (or a zero length string) and is not the name of any
  ** attached database, SQLITE_ERROR is returned to the caller.
  **
  ** ^Unless it returns SQLITE_MISUSE,
  ** the sqlite3_wal_checkpoint_v2() interface
  ** sets the error information that is queried by
  ** [sqlite3_errcode()] and [sqlite3_errmsg()].
  **
  ** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
  ** from SQL.
  */
  SQLITE_API int sqlite3_wal_checkpoint_v2(
    sqlite3 *db,                    /* Database handle */
    const char *zDb,                /* Name of attached database (or NULL) */
    int eMode,                      /* SQLITE_CHECKPOINT_* value */
    int *pnLog,                     /* OUT: Size of WAL log in frames */
    int *pnCkpt                     /* OUT: Total number of frames checkpointed */
  );
  
  /*
  ** CAPI3REF: Checkpoint Mode Values
  ** KEYWORDS: {checkpoint mode}
  **
  ** These constants define all valid values for the "checkpoint mode" passed
  ** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
  ** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
  ** meaning of each of these checkpoint modes.
  */
  #define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
  #define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
  #define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for for readers */
  #define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
  
  /*
  ** CAPI3REF: Virtual Table Interface Configuration
  **
  ** This function may be called by either the [xConnect] or [xCreate] method
  ** of a [virtual table] implementation to configure
  ** various facets of the virtual table interface.
  **
  ** If this interface is invoked outside the context of an xConnect or
  ** xCreate virtual table method then the behavior is undefined.
  **
  ** In the call sqlite3_vtab_config(D,C,...) the D parameter is the
  ** [database connection] in which the virtual table is being created and
  ** which is passed in as the first argument to the [xConnect] or [xCreate]
  ** method that is invoking sqlite3_vtab_config().  The C parameter is one
  ** of the [virtual table configuration options].  The presence and meaning
  ** of parameters after C depend on which [virtual table configuration option]
  ** is used.
  */
  SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
  
  /*
  ** CAPI3REF: Virtual Table Configuration Options
  ** KEYWORDS: {virtual table configuration options}
  ** KEYWORDS: {virtual table configuration option}
  **
  ** These macros define the various options to the
  ** [sqlite3_vtab_config()] interface that [virtual table] implementations
  ** can use to customize and optimize their behavior.
  **
  ** <dl>
  ** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]]
  ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt>
  ** <dd>Calls of the form
  ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
  ** where X is an integer.  If X is zero, then the [virtual table] whose
  ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
  ** support constraints.  In this configuration (which is the default) if
  ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
  ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
  ** specified as part of the users SQL statement, regardless of the actual
  ** ON CONFLICT mode specified.
  **
  ** If X is non-zero, then the virtual table implementation guarantees
  ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
  ** any modifications to internal or persistent data structures have been made.
  ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
  ** is able to roll back a statement or database transaction, and abandon
  ** or continue processing the current SQL statement as appropriate.
  ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
  ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
  ** had been ABORT.
  **
  ** Virtual table implementations that are required to handle OR REPLACE
  ** must do so within the [xUpdate] method. If a call to the
  ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
  ** CONFLICT policy is REPLACE, the virtual table implementation should
  ** silently replace the appropriate rows within the xUpdate callback and
  ** return SQLITE_OK. Or, if this is not possible, it may return
  ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
  ** constraint handling.
  ** </dd>
  **
  ** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt>
  ** <dd>Calls of the form
  ** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the
  ** the [xConnect] or [xCreate] methods of a [virtual table] implmentation
  ** prohibits that virtual table from being used from within triggers and
  ** views.
  ** </dd>
  **
  ** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt>
  ** <dd>Calls of the form
  ** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the
  ** the [xConnect] or [xCreate] methods of a [virtual table] implmentation
  ** identify that virtual table as being safe to use from within triggers
  ** and views.  Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the
  ** virtual table can do no serious harm even if it is controlled by a
  ** malicious hacker.  Developers should avoid setting the SQLITE_VTAB_INNOCUOUS
  ** flag unless absolutely necessary.
  ** </dd>
  ** </dl>
  */
  #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
  #define SQLITE_VTAB_INNOCUOUS          2
  #define SQLITE_VTAB_DIRECTONLY         3
  
  /*
  ** CAPI3REF: Determine The Virtual Table Conflict Policy
  **
  ** This function may only be called from within a call to the [xUpdate] method
  ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
  ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
  ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
  ** of the SQL statement that triggered the call to the [xUpdate] method of the
  ** [virtual table].
  */
  SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
  
  /*
  ** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
  **
  ** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
  ** method of a [virtual table], then it might return true if the
  ** column is being fetched as part of an UPDATE operation during which the
  ** column value will not change.  The virtual table implementation can use
  ** this hint as permission to substitute a return value that is less
  ** expensive to compute and that the corresponding
  ** [xUpdate] method understands as a "no-change" value.
  **
  ** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
  ** the column is not changed by the UPDATE statement, then the xColumn
  ** method can optionally return without setting a result, without calling
  ** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
  ** In that case, [sqlite3_value_nochange(X)] will return true for the
  ** same column in the [xUpdate] method.
  **
  ** The sqlite3_vtab_nochange() routine is an optimization.  Virtual table
  ** implementations should continue to give a correct answer even if the
  ** sqlite3_vtab_nochange() interface were to always return false.  In the
  ** current implementation, the sqlite3_vtab_nochange() interface does always
  ** returns false for the enhanced [UPDATE FROM] statement.
  */
  SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
  
  /*
  ** CAPI3REF: Determine The Collation For a Virtual Table Constraint
  **
  ** This function may only be called from within a call to the [xBestIndex]
  ** method of a [virtual table].
  **
  ** The first argument must be the sqlite3_index_info object that is the
  ** first parameter to the xBestIndex() method. The second argument must be
  ** an index into the aConstraint[] array belonging to the sqlite3_index_info
  ** structure passed to xBestIndex. This function returns a pointer to a buffer
  ** containing the name of the collation sequence for the corresponding
  ** constraint.
  */
  SQLITE_API SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
  
  /*
  ** CAPI3REF: Conflict resolution modes
  ** KEYWORDS: {conflict resolution mode}
  **
  ** These constants are returned by [sqlite3_vtab_on_conflict()] to
  ** inform a [virtual table] implementation what the [ON CONFLICT] mode
  ** is for the SQL statement being evaluated.
  **
  ** Note that the [SQLITE_IGNORE] constant is also used as a potential
  ** return value from the [sqlite3_set_authorizer()] callback and that
  ** [SQLITE_ABORT] is also a [result code].
  */
  #define SQLITE_ROLLBACK 1
  /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
  #define SQLITE_FAIL     3
  /* #define SQLITE_ABORT 4  // Also an error code */
  #define SQLITE_REPLACE  5
  
  /*
  ** CAPI3REF: Prepared Statement Scan Status Opcodes
  ** KEYWORDS: {scanstatus options}
  **
  ** The following constants can be used for the T parameter to the
  ** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
  ** different metric for sqlite3_stmt_scanstatus() to return.
  **
  ** When the value returned to V is a string, space to hold that string is
  ** managed by the prepared statement S and will be automatically freed when
  ** S is finalized.
  **
  ** <dl>
  ** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
  ** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be
  ** set to the total number of times that the X-th loop has run.</dd>
  **
  ** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
  ** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set
  ** to the total number of rows examined by all iterations of the X-th loop.</dd>
  **
  ** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
  ** <dd>^The "double" variable pointed to by the V parameter will be set to the
  ** query planner's estimate for the average number of rows output from each
  ** iteration of the X-th loop.  If the query planner's estimates was accurate,
  ** then this value will approximate the quotient NVISIT/NLOOP and the
  ** product of this value for all prior loops with the same SELECTID will
  ** be the NLOOP value for the current loop.
  **
  ** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
  ** <dd>^The "const char *" variable pointed to by the V parameter will be set
  ** to a zero-terminated UTF-8 string containing the name of the index or table
  ** used for the X-th loop.
  **
  ** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
  ** <dd>^The "const char *" variable pointed to by the V parameter will be set
  ** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
  ** description for the X-th loop.
  **
  ** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
  ** <dd>^The "int" variable pointed to by the V parameter will be set to the
  ** "select-id" for the X-th loop.  The select-id identifies which query or
  ** subquery the loop is part of.  The main query has a select-id of zero.
  ** The select-id is the same value as is output in the first column
  ** of an [EXPLAIN QUERY PLAN] query.
  ** </dl>
  */
  #define SQLITE_SCANSTAT_NLOOP    0
  #define SQLITE_SCANSTAT_NVISIT   1
  #define SQLITE_SCANSTAT_EST      2
  #define SQLITE_SCANSTAT_NAME     3
  #define SQLITE_SCANSTAT_EXPLAIN  4
  #define SQLITE_SCANSTAT_SELECTID 5
  
  /*
  ** CAPI3REF: Prepared Statement Scan Status
  ** METHOD: sqlite3_stmt
  **
  ** This interface returns information about the predicted and measured
  ** performance for pStmt.  Advanced applications can use this
  ** interface to compare the predicted and the measured performance and
  ** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
  **
  ** Since this interface is expected to be rarely used, it is only
  ** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
  ** compile-time option.
  **
  ** The "iScanStatusOp" parameter determines which status information to return.
  ** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
  ** of this interface is undefined.
  ** ^The requested measurement is written into a variable pointed to by
  ** the "pOut" parameter.
  ** Parameter "idx" identifies the specific loop to retrieve statistics for.
  ** Loops are numbered starting from zero. ^If idx is out of range - less than
  ** zero or greater than or equal to the total number of loops used to implement
  ** the statement - a non-zero value is returned and the variable that pOut
  ** points to is unchanged.
  **
  ** ^Statistics might not be available for all loops in all statements. ^In cases
  ** where there exist loops with no available statistics, this function behaves
  ** as if the loop did not exist - it returns non-zero and leave the variable
  ** that pOut points to unchanged.
  **
  ** See also: [sqlite3_stmt_scanstatus_reset()]
  */
  SQLITE_API int sqlite3_stmt_scanstatus(
    sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
    int idx,                  /* Index of loop to report on */
    int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
    void *pOut                /* Result written here */
  );
  
  /*
  ** CAPI3REF: Zero Scan-Status Counters
  ** METHOD: sqlite3_stmt
  **
  ** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
  **
  ** This API is only available if the library is built with pre-processor
  ** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
  */
  SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
  
  /*
  ** CAPI3REF: Flush caches to disk mid-transaction
  ** METHOD: sqlite3
  **
  ** ^If a write-transaction is open on [database connection] D when the
  ** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
  ** pages in the pager-cache that are not currently in use are written out
  ** to disk. A dirty page may be in use if a database cursor created by an
  ** active SQL statement is reading from it, or if it is page 1 of a database
  ** file (page 1 is always "in use").  ^The [sqlite3_db_cacheflush(D)]
  ** interface flushes caches for all schemas - "main", "temp", and
  ** any [attached] databases.
  **
  ** ^If this function needs to obtain extra database locks before dirty pages
  ** can be flushed to disk, it does so. ^If those locks cannot be obtained
  ** immediately and there is a busy-handler callback configured, it is invoked
  ** in the usual manner. ^If the required lock still cannot be obtained, then
  ** the database is skipped and an attempt made to flush any dirty pages
  ** belonging to the next (if any) database. ^If any databases are skipped
  ** because locks cannot be obtained, but no other error occurs, this
  ** function returns SQLITE_BUSY.
  **
  ** ^If any other error occurs while flushing dirty pages to disk (for
  ** example an IO error or out-of-memory condition), then processing is
  ** abandoned and an SQLite [error code] is returned to the caller immediately.
  **
  ** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
  **
  ** ^This function does not set the database handle error code or message
  ** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
  */
  SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
  
  /*
  ** CAPI3REF: The pre-update hook.
  ** METHOD: sqlite3
  **
  ** ^These interfaces are only available if SQLite is compiled using the
  ** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
  **
  ** ^The [sqlite3_preupdate_hook()] interface registers a callback function
  ** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
  ** on a database table.
  ** ^At most one preupdate hook may be registered at a time on a single
  ** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
  ** the previous setting.
  ** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
  ** with a NULL pointer as the second parameter.
  ** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
  ** the first parameter to callbacks.
  **
  ** ^The preupdate hook only fires for changes to real database tables; the
  ** preupdate hook is not invoked for changes to [virtual tables] or to
  ** system tables like sqlite_sequence or sqlite_stat1.
  **
  ** ^The second parameter to the preupdate callback is a pointer to
  ** the [database connection] that registered the preupdate hook.
  ** ^The third parameter to the preupdate callback is one of the constants
  ** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
  ** kind of update operation that is about to occur.
  ** ^(The fourth parameter to the preupdate callback is the name of the
  ** database within the database connection that is being modified.  This
  ** will be "main" for the main database or "temp" for TEMP tables or
  ** the name given after the AS keyword in the [ATTACH] statement for attached
  ** databases.)^
  ** ^The fifth parameter to the preupdate callback is the name of the
  ** table that is being modified.
  **
  ** For an UPDATE or DELETE operation on a [rowid table], the sixth
  ** parameter passed to the preupdate callback is the initial [rowid] of the
  ** row being modified or deleted. For an INSERT operation on a rowid table,
  ** or any operation on a WITHOUT ROWID table, the value of the sixth
  ** parameter is undefined. For an INSERT or UPDATE on a rowid table the
  ** seventh parameter is the final rowid value of the row being inserted
  ** or updated. The value of the seventh parameter passed to the callback
  ** function is not defined for operations on WITHOUT ROWID tables, or for
  ** DELETE operations on rowid tables.
  **
  ** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
  ** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
  ** provide additional information about a preupdate event. These routines
  ** may only be called from within a preupdate callback.  Invoking any of
  ** these routines from outside of a preupdate callback or with a
  ** [database connection] pointer that is different from the one supplied
  ** to the preupdate callback results in undefined and probably undesirable
  ** behavior.
  **
  ** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
  ** in the row that is being inserted, updated, or deleted.
  **
  ** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
  ** a [protected sqlite3_value] that contains the value of the Nth column of
  ** the table row before it is updated.  The N parameter must be between 0
  ** and one less than the number of columns or the behavior will be
  ** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
  ** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
  ** behavior is undefined.  The [sqlite3_value] that P points to
  ** will be destroyed when the preupdate callback returns.
  **
  ** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
  ** a [protected sqlite3_value] that contains the value of the Nth column of
  ** the table row after it is updated.  The N parameter must be between 0
  ** and one less than the number of columns or the behavior will be
  ** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
  ** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
  ** behavior is undefined.  The [sqlite3_value] that P points to
  ** will be destroyed when the preupdate callback returns.
  **
  ** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
  ** callback was invoked as a result of a direct insert, update, or delete
  ** operation; or 1 for inserts, updates, or deletes invoked by top-level
  ** triggers; or 2 for changes resulting from triggers called by top-level
  ** triggers; and so forth.
  **
  ** See also:  [sqlite3_update_hook()]
  */
  #if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
  SQLITE_API void *sqlite3_preupdate_hook(
    sqlite3 *db,
    void(*xPreUpdate)(
      void *pCtx,                   /* Copy of third arg to preupdate_hook() */
      sqlite3 *db,                  /* Database handle */
      int op,                       /* SQLITE_UPDATE, DELETE or INSERT */
      char const *zDb,              /* Database name */
      char const *zName,            /* Table name */
      sqlite3_int64 iKey1,          /* Rowid of row about to be deleted/updated */
      sqlite3_int64 iKey2           /* New rowid value (for a rowid UPDATE) */
    ),
    void*
  );
  SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
  SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
  SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
  SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
  #endif
  
  /*
  ** CAPI3REF: Low-level system error code
  ** METHOD: sqlite3
  **
  ** ^Attempt to return the underlying operating system error code or error
  ** number that caused the most recent I/O error or failure to open a file.
  ** The return value is OS-dependent.  For example, on unix systems, after
  ** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
  ** called to get back the underlying "errno" that caused the problem, such
  ** as ENOSPC, EAUTH, EISDIR, and so forth.
  */
  SQLITE_API int sqlite3_system_errno(sqlite3*);
  
  /*
  ** CAPI3REF: Database Snapshot
  ** KEYWORDS: {snapshot} {sqlite3_snapshot}
  **
  ** An instance of the snapshot object records the state of a [WAL mode]
  ** database for some specific point in history.
  **
  ** In [WAL mode], multiple [database connections] that are open on the
  ** same database file can each be reading a different historical version
  ** of the database file.  When a [database connection] begins a read
  ** transaction, that connection sees an unchanging copy of the database
  ** as it existed for the point in time when the transaction first started.
  ** Subsequent changes to the database from other connections are not seen
  ** by the reader until a new read transaction is started.
  **
  ** The sqlite3_snapshot object records state information about an historical
  ** version of the database file so that it is possible to later open a new read
  ** transaction that sees that historical version of the database rather than
  ** the most recent version.
  */
  typedef struct sqlite3_snapshot {
    unsigned char hidden[48];
  } sqlite3_snapshot;
  
  /*
  ** CAPI3REF: Record A Database Snapshot
  ** CONSTRUCTOR: sqlite3_snapshot
  **
  ** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
  ** new [sqlite3_snapshot] object that records the current state of
  ** schema S in database connection D.  ^On success, the
  ** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
  ** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
  ** If there is not already a read-transaction open on schema S when
  ** this function is called, one is opened automatically.
  **
  ** The following must be true for this function to succeed. If any of
  ** the following statements are false when sqlite3_snapshot_get() is
  ** called, SQLITE_ERROR is returned. The final value of *P is undefined
  ** in this case.
  **
  ** <ul>
  **   <li> The database handle must not be in [autocommit mode].
  **
  **   <li> Schema S of [database connection] D must be a [WAL mode] database.
  **
  **   <li> There must not be a write transaction open on schema S of database
  **        connection D.
  **
  **   <li> One or more transactions must have been written to the current wal
  **        file since it was created on disk (by any connection). This means
  **        that a snapshot cannot be taken on a wal mode database with no wal
  **        file immediately after it is first opened. At least one transaction
  **        must be written to it first.
  ** </ul>
  **
  ** This function may also return SQLITE_NOMEM.  If it is called with the
  ** database handle in autocommit mode but fails for some other reason,
  ** whether or not a read transaction is opened on schema S is undefined.
  **
  ** The [sqlite3_snapshot] object returned from a successful call to
  ** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
  ** to avoid a memory leak.
  **
  ** The [sqlite3_snapshot_get()] interface is only available when the
  ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
  */
  SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
    sqlite3 *db,
    const char *zSchema,
    sqlite3_snapshot **ppSnapshot
  );
  
  /*
  ** CAPI3REF: Start a read transaction on an historical snapshot
  ** METHOD: sqlite3_snapshot
  **
  ** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read
  ** transaction or upgrades an existing one for schema S of
  ** [database connection] D such that the read transaction refers to
  ** historical [snapshot] P, rather than the most recent change to the
  ** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK
  ** on success or an appropriate [error code] if it fails.
  **
  ** ^In order to succeed, the database connection must not be in
  ** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there
  ** is already a read transaction open on schema S, then the database handle
  ** must have no active statements (SELECT statements that have been passed
  ** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
  ** SQLITE_ERROR is returned if either of these conditions is violated, or
  ** if schema S does not exist, or if the snapshot object is invalid.
  **
  ** ^A call to sqlite3_snapshot_open() will fail to open if the specified
  ** snapshot has been overwritten by a [checkpoint]. In this case
  ** SQLITE_ERROR_SNAPSHOT is returned.
  **
  ** If there is already a read transaction open when this function is
  ** invoked, then the same read transaction remains open (on the same
  ** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
  ** is returned. If another error code - for example SQLITE_PROTOCOL or an
  ** SQLITE_IOERR error code - is returned, then the final state of the
  ** read transaction is undefined. If SQLITE_OK is returned, then the
  ** read transaction is now open on database snapshot P.
  **
  ** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
  ** database connection D does not know that the database file for
  ** schema S is in [WAL mode].  A database connection might not know
  ** that the database file is in [WAL mode] if there has been no prior
  ** I/O on that database connection, or if the database entered [WAL mode]
  ** after the most recent I/O on the database connection.)^
  ** (Hint: Run "[PRAGMA application_id]" against a newly opened
  ** database connection in order to make it ready to use snapshots.)
  **
  ** The [sqlite3_snapshot_open()] interface is only available when the
  ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
  */
  SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
    sqlite3 *db,
    const char *zSchema,
    sqlite3_snapshot *pSnapshot
  );
  
  /*
  ** CAPI3REF: Destroy a snapshot
  ** DESTRUCTOR: sqlite3_snapshot
  **
  ** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
  ** The application must eventually free every [sqlite3_snapshot] object
  ** using this routine to avoid a memory leak.
  **
  ** The [sqlite3_snapshot_free()] interface is only available when the
  ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
  */
  SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
  
  /*
  ** CAPI3REF: Compare the ages of two snapshot handles.
  ** METHOD: sqlite3_snapshot
  **
  ** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
  ** of two valid snapshot handles.
  **
  ** If the two snapshot handles are not associated with the same database
  ** file, the result of the comparison is undefined.
  **
  ** Additionally, the result of the comparison is only valid if both of the
  ** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
  ** last time the wal file was deleted. The wal file is deleted when the
  ** database is changed back to rollback mode or when the number of database
  ** clients drops to zero. If either snapshot handle was obtained before the
  ** wal file was last deleted, the value returned by this function
  ** is undefined.
  **
  ** Otherwise, this API returns a negative value if P1 refers to an older
  ** snapshot than P2, zero if the two handles refer to the same database
  ** snapshot, and a positive value if P1 is a newer snapshot than P2.
  **
  ** This interface is only available if SQLite is compiled with the
  ** [SQLITE_ENABLE_SNAPSHOT] option.
  */
  SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
    sqlite3_snapshot *p1,
    sqlite3_snapshot *p2
  );
  
  /*
  ** CAPI3REF: Recover snapshots from a wal file
  ** METHOD: sqlite3_snapshot
  **
  ** If a [WAL file] remains on disk after all database connections close
  ** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control]
  ** or because the last process to have the database opened exited without
  ** calling [sqlite3_close()]) and a new connection is subsequently opened
  ** on that database and [WAL file], the [sqlite3_snapshot_open()] interface
  ** will only be able to open the last transaction added to the WAL file
  ** even though the WAL file contains other valid transactions.
  **
  ** This function attempts to scan the WAL file associated with database zDb
  ** of database handle db and make all valid snapshots available to
  ** sqlite3_snapshot_open(). It is an error if there is already a read
  ** transaction open on the database, or if the database is not a WAL mode
  ** database.
  **
  ** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
  **
  ** This interface is only available if SQLite is compiled with the
  ** [SQLITE_ENABLE_SNAPSHOT] option.
  */
  SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
  
  /*
  ** CAPI3REF: Serialize a database
  **
  ** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory
  ** that is a serialization of the S database on [database connection] D.
  ** If P is not a NULL pointer, then the size of the database in bytes
  ** is written into *P.
  **
  ** For an ordinary on-disk database file, the serialization is just a
  ** copy of the disk file.  For an in-memory database or a "TEMP" database,
  ** the serialization is the same sequence of bytes which would be written
  ** to disk if that database where backed up to disk.
  **
  ** The usual case is that sqlite3_serialize() copies the serialization of
  ** the database into memory obtained from [sqlite3_malloc64()] and returns
  ** a pointer to that memory.  The caller is responsible for freeing the
  ** returned value to avoid a memory leak.  However, if the F argument
  ** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
  ** are made, and the sqlite3_serialize() function will return a pointer
  ** to the contiguous memory representation of the database that SQLite
  ** is currently using for that database, or NULL if the no such contiguous
  ** memory representation of the database exists.  A contiguous memory
  ** representation of the database will usually only exist if there has
  ** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
  ** values of D and S.
  ** The size of the database is written into *P even if the
  ** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
  ** of the database exists.
  **
  ** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
  ** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
  ** allocation error occurs.
  **
  ** This interface is only available if SQLite is compiled with the
  ** [SQLITE_ENABLE_DESERIALIZE] option.
  */
  SQLITE_API unsigned char *sqlite3_serialize(
    sqlite3 *db,           /* The database connection */
    const char *zSchema,   /* Which DB to serialize. ex: "main", "temp", ... */
    sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
    unsigned int mFlags    /* Zero or more SQLITE_SERIALIZE_* flags */
  );
  
  /*
  ** CAPI3REF: Flags for sqlite3_serialize
  **
  ** Zero or more of the following constants can be OR-ed together for
  ** the F argument to [sqlite3_serialize(D,S,P,F)].
  **
  ** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
  ** a pointer to contiguous in-memory database that it is currently using,
  ** without making a copy of the database.  If SQLite is not currently using
  ** a contiguous in-memory database, then this option causes
  ** [sqlite3_serialize()] to return a NULL pointer.  SQLite will only be
  ** using a contiguous in-memory database if it has been initialized by a
  ** prior call to [sqlite3_deserialize()].
  */
  #define SQLITE_SERIALIZE_NOCOPY 0x001   /* Do no memory allocations */
  
  /*
  ** CAPI3REF: Deserialize a database
  **
  ** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
  ** [database connection] D to disconnect from database S and then
  ** reopen S as an in-memory database based on the serialization contained
  ** in P.  The serialized database P is N bytes in size.  M is the size of
  ** the buffer P, which might be larger than N.  If M is larger than N, and
  ** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
  ** permitted to add content to the in-memory database as long as the total
  ** size does not exceed M bytes.
  **
  ** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
  ** invoke sqlite3_free() on the serialization buffer when the database
  ** connection closes.  If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
  ** SQLite will try to increase the buffer size using sqlite3_realloc64()
  ** if writes on the database cause it to grow larger than M bytes.
  **
  ** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
  ** database is currently in a read transaction or is involved in a backup
  ** operation.
  **
  ** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
  ** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
  ** [sqlite3_free()] is invoked on argument P prior to returning.
  **
  ** This interface is only available if SQLite is compiled with the
  ** [SQLITE_ENABLE_DESERIALIZE] option.
  */
  SQLITE_API int sqlite3_deserialize(
    sqlite3 *db,            /* The database connection */
    const char *zSchema,    /* Which DB to reopen with the deserialization */
    unsigned char *pData,   /* The serialized database content */
    sqlite3_int64 szDb,     /* Number bytes in the deserialization */
    sqlite3_int64 szBuf,    /* Total size of buffer pData[] */
    unsigned mFlags         /* Zero or more SQLITE_DESERIALIZE_* flags */
  );
  
  /*
  ** CAPI3REF: Flags for sqlite3_deserialize()
  **
  ** The following are allowed values for 6th argument (the F argument) to
  ** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
  **
  ** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
  ** in the P argument is held in memory obtained from [sqlite3_malloc64()]
  ** and that SQLite should take ownership of this memory and automatically
  ** free it when it has finished using it.  Without this flag, the caller
  ** is responsible for freeing any dynamically allocated memory.
  **
  ** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
  ** grow the size of the database using calls to [sqlite3_realloc64()].  This
  ** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
  ** Without this flag, the deserialized database cannot increase in size beyond
  ** the number of bytes specified by the M parameter.
  **
  ** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
  ** should be treated as read-only.
  */
  #define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
  #define SQLITE_DESERIALIZE_RESIZEABLE  2 /* Resize using sqlite3_realloc64() */
  #define SQLITE_DESERIALIZE_READONLY    4 /* Database is read-only */
  
  /*
  ** Undo the hack that converts floating point types to integer for
  ** builds on processors without floating point support.
  */
  #ifdef SQLITE_OMIT_FLOATING_POINT
  # undef double
  #endif
  
  #ifdef __cplusplus
  }  /* End of the 'extern "C"' block */
  #endif
  #endif /* SQLITE3_H */
  
  /******** Begin file sqlite3rtree.h *********/
  /*
  ** 2010 August 30
  **
  ** The author disclaims copyright to this source code.  In place of
  ** a legal notice, here is a blessing:
  **
  **    May you do good and not evil.
  **    May you find forgiveness for yourself and forgive others.
  **    May you share freely, never taking more than you give.
  **
  *************************************************************************
  */
  
  #ifndef _SQLITE3RTREE_H_
  #define _SQLITE3RTREE_H_
  
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
  typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
  
  /* The double-precision datatype used by RTree depends on the
  ** SQLITE_RTREE_INT_ONLY compile-time option.
  */
  #ifdef SQLITE_RTREE_INT_ONLY
    typedef sqlite3_int64 sqlite3_rtree_dbl;
  #else
    typedef double sqlite3_rtree_dbl;
  #endif
  
  /*
  ** Register a geometry callback named zGeom that can be used as part of an
  ** R-Tree geometry query as follows:
  **
  **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
  */
  SQLITE_API int sqlite3_rtree_geometry_callback(
    sqlite3 *db,
    const char *zGeom,
    int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
    void *pContext
  );
  
  
  /*
  ** A pointer to a structure of the following type is passed as the first
  ** argument to callbacks registered using rtree_geometry_callback().
  */
  struct sqlite3_rtree_geometry {
    void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
    int nParam;                     /* Size of array aParam[] */
    sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
    void *pUser;                    /* Callback implementation user data */
    void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
  };
  
  /*
  ** Register a 2nd-generation geometry callback named zScore that can be
  ** used as part of an R-Tree geometry query as follows:
  **
  **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
  */
  SQLITE_API int sqlite3_rtree_query_callback(
    sqlite3 *db,
    const char *zQueryFunc,
    int (*xQueryFunc)(sqlite3_rtree_query_info*),
    void *pContext,
    void (*xDestructor)(void*)
  );
  
  
  /*
  ** A pointer to a structure of the following type is passed as the
  ** argument to scored geometry callback registered using
  ** sqlite3_rtree_query_callback().
  **
  ** Note that the first 5 fields of this structure are identical to
  ** sqlite3_rtree_geometry.  This structure is a subclass of
  ** sqlite3_rtree_geometry.
  */
  struct sqlite3_rtree_query_info {
    void *pContext;                   /* pContext from when function registered */
    int nParam;                       /* Number of function parameters */
    sqlite3_rtree_dbl *aParam;        /* value of function parameters */
    void *pUser;                      /* callback can use this, if desired */
    void (*xDelUser)(void*);          /* function to free pUser */
    sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
    unsigned int *anQueue;            /* Number of pending entries in the queue */
    int nCoord;                       /* Number of coordinates */
    int iLevel;                       /* Level of current node or entry */
    int mxLevel;                      /* The largest iLevel value in the tree */
    sqlite3_int64 iRowid;             /* Rowid for current entry */
    sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
    int eParentWithin;                /* Visibility of parent node */
    int eWithin;                      /* OUT: Visibility */
    sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
    /* The following fields are only available in 3.8.11 and later */
    sqlite3_value **apSqlParam;       /* Original SQL values of parameters */
  };
  
  /*
  ** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
  */
  #define NOT_WITHIN       0   /* Object completely outside of query region */
  #define PARTLY_WITHIN    1   /* Object partially overlaps query region */
  #define FULLY_WITHIN     2   /* Object fully contained within query region */
  
  
  #ifdef __cplusplus
  }  /* end of the 'extern "C"' block */
  #endif
  
  #endif  /* ifndef _SQLITE3RTREE_H_ */
  
  /******** End of sqlite3rtree.h *********/
  /******** Begin file sqlite3session.h *********/
  
  #if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
  #define __SQLITESESSION_H_ 1
  
  /*
  ** Make sure we can call this stuff from C++.
  */
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  
  /*
  ** CAPI3REF: Session Object Handle
  **
  ** An instance of this object is a [session] that can be used to
  ** record changes to a database.
  */
  typedef struct sqlite3_session sqlite3_session;
  
  /*
  ** CAPI3REF: Changeset Iterator Handle
  **
  ** An instance of this object acts as a cursor for iterating
  ** over the elements of a [changeset] or [patchset].
  */
  typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
  
  /*
  ** CAPI3REF: Create A New Session Object
  ** CONSTRUCTOR: sqlite3_session
  **
  ** Create a new session object attached to database handle db. If successful,
  ** a pointer to the new object is written to *ppSession and SQLITE_OK is
  ** returned. If an error occurs, *ppSession is set to NULL and an SQLite
  ** error code (e.g. SQLITE_NOMEM) is returned.
  **
  ** It is possible to create multiple session objects attached to a single
  ** database handle.
  **
  ** Session objects created using this function should be deleted using the
  ** [sqlite3session_delete()] function before the database handle that they
  ** are attached to is itself closed. If the database handle is closed before
  ** the session object is deleted, then the results of calling any session
  ** module function, including [sqlite3session_delete()] on the session object
  ** are undefined.
  **
  ** Because the session module uses the [sqlite3_preupdate_hook()] API, it
  ** is not possible for an application to register a pre-update hook on a
  ** database handle that has one or more session objects attached. Nor is
  ** it possible to create a session object attached to a database handle for
  ** which a pre-update hook is already defined. The results of attempting
  ** either of these things are undefined.
  **
  ** The session object will be used to create changesets for tables in
  ** database zDb, where zDb is either "main", or "temp", or the name of an
  ** attached database. It is not an error if database zDb is not attached
  ** to the database when the session object is created.
  */
  SQLITE_API int sqlite3session_create(
    sqlite3 *db,                    /* Database handle */
    const char *zDb,                /* Name of db (e.g. "main") */
    sqlite3_session **ppSession     /* OUT: New session object */
  );
  
  /*
  ** CAPI3REF: Delete A Session Object
  ** DESTRUCTOR: sqlite3_session
  **
  ** Delete a session object previously allocated using
  ** [sqlite3session_create()]. Once a session object has been deleted, the
  ** results of attempting to use pSession with any other session module
  ** function are undefined.
  **
  ** Session objects must be deleted before the database handle to which they
  ** are attached is closed. Refer to the documentation for
  ** [sqlite3session_create()] for details.
  */
  SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
  
  
  /*
  ** CAPI3REF: Enable Or Disable A Session Object
  ** METHOD: sqlite3_session
  **
  ** Enable or disable the recording of changes by a session object. When
  ** enabled, a session object records changes made to the database. When
  ** disabled - it does not. A newly created session object is enabled.
  ** Refer to the documentation for [sqlite3session_changeset()] for further
  ** details regarding how enabling and disabling a session object affects
  ** the eventual changesets.
  **
  ** Passing zero to this function disables the session. Passing a value
  ** greater than zero enables it. Passing a value less than zero is a
  ** no-op, and may be used to query the current state of the session.
  **
  ** The return value indicates the final state of the session object: 0 if
  ** the session is disabled, or 1 if it is enabled.
  */
  SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
  
  /*
  ** CAPI3REF: Set Or Clear the Indirect Change Flag
  ** METHOD: sqlite3_session
  **
  ** Each change recorded by a session object is marked as either direct or
  ** indirect. A change is marked as indirect if either:
  **
  ** <ul>
  **   <li> The session object "indirect" flag is set when the change is
  **        made, or
  **   <li> The change is made by an SQL trigger or foreign key action
  **        instead of directly as a result of a users SQL statement.
  ** </ul>
  **
  ** If a single row is affected by more than one operation within a session,
  ** then the change is considered indirect if all operations meet the criteria
  ** for an indirect change above, or direct otherwise.
  **
  ** This function is used to set, clear or query the session object indirect
  ** flag.  If the second argument passed to this function is zero, then the
  ** indirect flag is cleared. If it is greater than zero, the indirect flag
  ** is set. Passing a value less than zero does not modify the current value
  ** of the indirect flag, and may be used to query the current state of the
  ** indirect flag for the specified session object.
  **
  ** The return value indicates the final state of the indirect flag: 0 if
  ** it is clear, or 1 if it is set.
  */
  SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
  
  /*
  ** CAPI3REF: Attach A Table To A Session Object
  ** METHOD: sqlite3_session
  **
  ** If argument zTab is not NULL, then it is the name of a table to attach
  ** to the session object passed as the first argument. All subsequent changes
  ** made to the table while the session object is enabled will be recorded. See
  ** documentation for [sqlite3session_changeset()] for further details.
  **
  ** Or, if argument zTab is NULL, then changes are recorded for all tables
  ** in the database. If additional tables are added to the database (by
  ** executing "CREATE TABLE" statements) after this call is made, changes for
  ** the new tables are also recorded.
  **
  ** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
  ** defined as part of their CREATE TABLE statement. It does not matter if the
  ** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
  ** KEY may consist of a single column, or may be a composite key.
  **
  ** It is not an error if the named table does not exist in the database. Nor
  ** is it an error if the named table does not have a PRIMARY KEY. However,
  ** no changes will be recorded in either of these scenarios.
  **
  ** Changes are not recorded for individual rows that have NULL values stored
  ** in one or more of their PRIMARY KEY columns.
  **
  ** SQLITE_OK is returned if the call completes without error. Or, if an error
  ** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
  **
  ** <h3>Special sqlite_stat1 Handling</h3>
  **
  ** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to
  ** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
  **  <pre>
  **  &nbsp;     CREATE TABLE sqlite_stat1(tbl,idx,stat)
  **  </pre>
  **
  ** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are
  ** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes
  ** are recorded for rows for which (idx IS NULL) is true. However, for such
  ** rows a zero-length blob (SQL value X'') is stored in the changeset or
  ** patchset instead of a NULL value. This allows such changesets to be
  ** manipulated by legacy implementations of sqlite3changeset_invert(),
  ** concat() and similar.
  **
  ** The sqlite3changeset_apply() function automatically converts the
  ** zero-length blob back to a NULL value when updating the sqlite_stat1
  ** table. However, if the application calls sqlite3changeset_new(),
  ** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset
  ** iterator directly (including on a changeset iterator passed to a
  ** conflict-handler callback) then the X'' value is returned. The application
  ** must translate X'' to NULL itself if required.
  **
  ** Legacy (older than 3.22.0) versions of the sessions module cannot capture
  ** changes made to the sqlite_stat1 table. Legacy versions of the
  ** sqlite3changeset_apply() function silently ignore any modifications to the
  ** sqlite_stat1 table that are part of a changeset or patchset.
  */
  SQLITE_API int sqlite3session_attach(
    sqlite3_session *pSession,      /* Session object */
    const char *zTab                /* Table name */
  );
  
  /*
  ** CAPI3REF: Set a table filter on a Session Object.
  ** METHOD: sqlite3_session
  **
  ** The second argument (xFilter) is the "filter callback". For changes to rows
  ** in tables that are not attached to the Session object, the filter is called
  ** to determine whether changes to the table's rows should be tracked or not.
  ** If xFilter returns 0, changes are not tracked. Note that once a table is
  ** attached, xFilter will not be called again.
  */
  SQLITE_API void sqlite3session_table_filter(
    sqlite3_session *pSession,      /* Session object */
    int(*xFilter)(
      void *pCtx,                   /* Copy of third arg to _filter_table() */
      const char *zTab              /* Table name */
    ),
    void *pCtx                      /* First argument passed to xFilter */
  );
  
  /*
  ** CAPI3REF: Generate A Changeset From A Session Object
  ** METHOD: sqlite3_session
  **
  ** Obtain a changeset containing changes to the tables attached to the
  ** session object passed as the first argument. If successful,
  ** set *ppChangeset to point to a buffer containing the changeset
  ** and *pnChangeset to the size of the changeset in bytes before returning
  ** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
  ** zero and return an SQLite error code.
  **
  ** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
  ** each representing a change to a single row of an attached table. An INSERT
  ** change contains the values of each field of a new database row. A DELETE
  ** contains the original values of each field of a deleted database row. An
  ** UPDATE change contains the original values of each field of an updated
  ** database row along with the updated values for each updated non-primary-key
  ** column. It is not possible for an UPDATE change to represent a change that
  ** modifies the values of primary key columns. If such a change is made, it
  ** is represented in a changeset as a DELETE followed by an INSERT.
  **
  ** Changes are not recorded for rows that have NULL values stored in one or
  ** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
  ** no corresponding change is present in the changesets returned by this
  ** function. If an existing row with one or more NULL values stored in
  ** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
  ** only an INSERT is appears in the changeset. Similarly, if an existing row
  ** with non-NULL PRIMARY KEY values is updated so that one or more of its
  ** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
  ** DELETE change only.
  **
  ** The contents of a changeset may be traversed using an iterator created
  ** using the [sqlite3changeset_start()] API. A changeset may be applied to
  ** a database with a compatible schema using the [sqlite3changeset_apply()]
  ** API.
  **
  ** Within a changeset generated by this function, all changes related to a
  ** single table are grouped together. In other words, when iterating through
  ** a changeset or when applying a changeset to a database, all changes related
  ** to a single table are processed before moving on to the next table. Tables
  ** are sorted in the same order in which they were attached (or auto-attached)
  ** to the sqlite3_session object. The order in which the changes related to
  ** a single table are stored is undefined.
  **
  ** Following a successful call to this function, it is the responsibility of
  ** the caller to eventually free the buffer that *ppChangeset points to using
  ** [sqlite3_free()].
  **
  ** <h3>Changeset Generation</h3>
  **
  ** Once a table has been attached to a session object, the session object
  ** records the primary key values of all new rows inserted into the table.
  ** It also records the original primary key and other column values of any
  ** deleted or updated rows. For each unique primary key value, data is only
  ** recorded once - the first time a row with said primary key is inserted,
  ** updated or deleted in the lifetime of the session.
  **
  ** There is one exception to the previous paragraph: when a row is inserted,
  ** updated or deleted, if one or more of its primary key columns contain a
  ** NULL value, no record of the change is made.
  **
  ** The session object therefore accumulates two types of records - those
  ** that consist of primary key values only (created when the user inserts
  ** a new record) and those that consist of the primary key values and the
  ** original values of other table columns (created when the users deletes
  ** or updates a record).
  **
  ** When this function is called, the requested changeset is created using
  ** both the accumulated records and the current contents of the database
  ** file. Specifically:
  **
  ** <ul>
  **   <li> For each record generated by an insert, the database is queried
  **        for a row with a matching primary key. If one is found, an INSERT
  **        change is added to the changeset. If no such row is found, no change
  **        is added to the changeset.
  **
  **   <li> For each record generated by an update or delete, the database is
  **        queried for a row with a matching primary key. If such a row is
  **        found and one or more of the non-primary key fields have been
  **        modified from their original values, an UPDATE change is added to
  **        the changeset. Or, if no such row is found in the table, a DELETE
  **        change is added to the changeset. If there is a row with a matching
  **        primary key in the database, but all fields contain their original
  **        values, no change is added to the changeset.
  ** </ul>
  **
  ** This means, amongst other things, that if a row is inserted and then later
  ** deleted while a session object is active, neither the insert nor the delete
  ** will be present in the changeset. Or if a row is deleted and then later a
  ** row with the same primary key values inserted while a session object is
  ** active, the resulting changeset will contain an UPDATE change instead of
  ** a DELETE and an INSERT.
  **
  ** When a session object is disabled (see the [sqlite3session_enable()] API),
  ** it does not accumulate records when rows are inserted, updated or deleted.
  ** This may appear to have some counter-intuitive effects if a single row
  ** is written to more than once during a session. For example, if a row
  ** is inserted while a session object is enabled, then later deleted while
  ** the same session object is disabled, no INSERT record will appear in the
  ** changeset, even though the delete took place while the session was disabled.
  ** Or, if one field of a row is updated while a session is disabled, and
  ** another field of the same row is updated while the session is enabled, the
  ** resulting changeset will contain an UPDATE change that updates both fields.
  */
  SQLITE_API int sqlite3session_changeset(
    sqlite3_session *pSession,      /* Session object */
    int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
    void **ppChangeset              /* OUT: Buffer containing changeset */
  );
  
  /*
  ** CAPI3REF: Load The Difference Between Tables Into A Session
  ** METHOD: sqlite3_session
  **
  ** If it is not already attached to the session object passed as the first
  ** argument, this function attaches table zTbl in the same manner as the
  ** [sqlite3session_attach()] function. If zTbl does not exist, or if it
  ** does not have a primary key, this function is a no-op (but does not return
  ** an error).
  **
  ** Argument zFromDb must be the name of a database ("main", "temp" etc.)
  ** attached to the same database handle as the session object that contains
  ** a table compatible with the table attached to the session by this function.
  ** A table is considered compatible if it:
  **
  ** <ul>
  **   <li> Has the same name,
  **   <li> Has the same set of columns declared in the same order, and
  **   <li> Has the same PRIMARY KEY definition.
  ** </ul>
  **
  ** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
  ** are compatible but do not have any PRIMARY KEY columns, it is not an error
  ** but no changes are added to the session object. As with other session
  ** APIs, tables without PRIMARY KEYs are simply ignored.
  **
  ** This function adds a set of changes to the session object that could be
  ** used to update the table in database zFrom (call this the "from-table")
  ** so that its content is the same as the table attached to the session
  ** object (call this the "to-table"). Specifically:
  **
  ** <ul>
  **   <li> For each row (primary key) that exists in the to-table but not in
  **     the from-table, an INSERT record is added to the session object.
  **
  **   <li> For each row (primary key) that exists in the to-table but not in
  **     the from-table, a DELETE record is added to the session object.
  **
  **   <li> For each row (primary key) that exists in both tables, but features
  **     different non-PK values in each, an UPDATE record is added to the
  **     session.
  ** </ul>
  **
  ** To clarify, if this function is called and then a changeset constructed
  ** using [sqlite3session_changeset()], then after applying that changeset to
  ** database zFrom the contents of the two compatible tables would be
  ** identical.
  **
  ** It an error if database zFrom does not exist or does not contain the
  ** required compatible table.
  **
  ** If the operation is successful, SQLITE_OK is returned. Otherwise, an SQLite
  ** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
  ** may be set to point to a buffer containing an English language error
  ** message. It is the responsibility of the caller to free this buffer using
  ** sqlite3_free().
  */
  SQLITE_API int sqlite3session_diff(
    sqlite3_session *pSession,
    const char *zFromDb,
    const char *zTbl,
    char **pzErrMsg
  );
  
  
  /*
  ** CAPI3REF: Generate A Patchset From A Session Object
  ** METHOD: sqlite3_session
  **
  ** The differences between a patchset and a changeset are that:
  **
  ** <ul>
  **   <li> DELETE records consist of the primary key fields only. The
  **        original values of other fields are omitted.
  **   <li> The original values of any modified fields are omitted from
  **        UPDATE records.
  ** </ul>
  **
  ** A patchset blob may be used with up to date versions of all
  ** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
  ** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
  ** attempting to use a patchset blob with old versions of the
  ** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
  **
  ** Because the non-primary key "old.*" fields are omitted, no
  ** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
  ** is passed to the sqlite3changeset_apply() API. Other conflict types work
  ** in the same way as for changesets.
  **
  ** Changes within a patchset are ordered in the same way as for changesets
  ** generated by the sqlite3session_changeset() function (i.e. all changes for
  ** a single table are grouped together, tables appear in the order in which
  ** they were attached to the session object).
  */
  SQLITE_API int sqlite3session_patchset(
    sqlite3_session *pSession,      /* Session object */
    int *pnPatchset,                /* OUT: Size of buffer at *ppPatchset */
    void **ppPatchset               /* OUT: Buffer containing patchset */
  );
  
  /*
  ** CAPI3REF: Test if a changeset has recorded any changes.
  **
  ** Return non-zero if no changes to attached tables have been recorded by
  ** the session object passed as the first argument. Otherwise, if one or
  ** more changes have been recorded, return zero.
  **
  ** Even if this function returns zero, it is possible that calling
  ** [sqlite3session_changeset()] on the session handle may still return a
  ** changeset that contains no changes. This can happen when a row in
  ** an attached table is modified and then later on the original values
  ** are restored. However, if this function returns non-zero, then it is
  ** guaranteed that a call to sqlite3session_changeset() will return a
  ** changeset containing zero changes.
  */
  SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
  
  /*
  ** CAPI3REF: Create An Iterator To Traverse A Changeset
  ** CONSTRUCTOR: sqlite3_changeset_iter
  **
  ** Create an iterator used to iterate through the contents of a changeset.
  ** If successful, *pp is set to point to the iterator handle and SQLITE_OK
  ** is returned. Otherwise, if an error occurs, *pp is set to zero and an
  ** SQLite error code is returned.
  **
  ** The following functions can be used to advance and query a changeset
  ** iterator created by this function:
  **
  ** <ul>
  **   <li> [sqlite3changeset_next()]
  **   <li> [sqlite3changeset_op()]
  **   <li> [sqlite3changeset_new()]
  **   <li> [sqlite3changeset_old()]
  ** </ul>
  **
  ** It is the responsibility of the caller to eventually destroy the iterator
  ** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
  ** changeset (pChangeset) must remain valid until after the iterator is
  ** destroyed.
  **
  ** Assuming the changeset blob was created by one of the
  ** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
  ** [sqlite3changeset_invert()] functions, all changes within the changeset
  ** that apply to a single table are grouped together. This means that when
  ** an application iterates through a changeset using an iterator created by
  ** this function, all changes that relate to a single table are visited
  ** consecutively. There is no chance that the iterator will visit a change
  ** the applies to table X, then one for table Y, and then later on visit
  ** another change for table X.
  **
  ** The behavior of sqlite3changeset_start_v2() and its streaming equivalent
  ** may be modified by passing a combination of
  ** [SQLITE_CHANGESETSTART_INVERT | supported flags] as the 4th parameter.
  **
  ** Note that the sqlite3changeset_start_v2() API is still <b>experimental</b>
  ** and therefore subject to change.
  */
  SQLITE_API int sqlite3changeset_start(
    sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
    int nChangeset,                 /* Size of changeset blob in bytes */
    void *pChangeset                /* Pointer to blob containing changeset */
  );
  SQLITE_API int sqlite3changeset_start_v2(
    sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
    int nChangeset,                 /* Size of changeset blob in bytes */
    void *pChangeset,               /* Pointer to blob containing changeset */
    int flags                       /* SESSION_CHANGESETSTART_* flags */
  );
  
  /*
  ** CAPI3REF: Flags for sqlite3changeset_start_v2
  **
  ** The following flags may passed via the 4th parameter to
  ** [sqlite3changeset_start_v2] and [sqlite3changeset_start_v2_strm]:
  **
  ** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
  **   Invert the changeset while iterating through it. This is equivalent to
  **   inverting a changeset using sqlite3changeset_invert() before applying it.
  **   It is an error to specify this flag with a patchset.
  */
  #define SQLITE_CHANGESETSTART_INVERT        0x0002
  
  
  /*
  ** CAPI3REF: Advance A Changeset Iterator
  ** METHOD: sqlite3_changeset_iter
  **
  ** This function may only be used with iterators created by the function
  ** [sqlite3changeset_start()]. If it is called on an iterator passed to
  ** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
  ** is returned and the call has no effect.
  **
  ** Immediately after an iterator is created by sqlite3changeset_start(), it
  ** does not point to any change in the changeset. Assuming the changeset
  ** is not empty, the first call to this function advances the iterator to
  ** point to the first change in the changeset. Each subsequent call advances
  ** the iterator to point to the next change in the changeset (if any). If
  ** no error occurs and the iterator points to a valid change after a call
  ** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
  ** Otherwise, if all changes in the changeset have already been visited,
  ** SQLITE_DONE is returned.
  **
  ** If an error occurs, an SQLite error code is returned. Possible error
  ** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
  ** SQLITE_NOMEM.
  */
  SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
  
  /*
  ** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
  ** METHOD: sqlite3_changeset_iter
  **
  ** The pIter argument passed to this function may either be an iterator
  ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
  ** created by [sqlite3changeset_start()]. In the latter case, the most recent
  ** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
  ** is not the case, this function returns [SQLITE_MISUSE].
  **
  ** If argument pzTab is not NULL, then *pzTab is set to point to a
  ** nul-terminated utf-8 encoded string containing the name of the table
  ** affected by the current change. The buffer remains valid until either
  ** sqlite3changeset_next() is called on the iterator or until the
  ** conflict-handler function returns. If pnCol is not NULL, then *pnCol is
  ** set to the number of columns in the table affected by the change. If
  ** pbIndirect is not NULL, then *pbIndirect is set to true (1) if the change
  ** is an indirect change, or false (0) otherwise. See the documentation for
  ** [sqlite3session_indirect()] for a description of direct and indirect
  ** changes. Finally, if pOp is not NULL, then *pOp is set to one of
  ** [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE], depending on the
  ** type of change that the iterator currently points to.
  **
  ** If no error occurs, SQLITE_OK is returned. If an error does occur, an
  ** SQLite error code is returned. The values of the output variables may not
  ** be trusted in this case.
  */
  SQLITE_API int sqlite3changeset_op(
    sqlite3_changeset_iter *pIter,  /* Iterator object */
    const char **pzTab,             /* OUT: Pointer to table name */
    int *pnCol,                     /* OUT: Number of columns in table */
    int *pOp,                       /* OUT: SQLITE_INSERT, DELETE or UPDATE */
    int *pbIndirect                 /* OUT: True for an 'indirect' change */
  );
  
  /*
  ** CAPI3REF: Obtain The Primary Key Definition Of A Table
  ** METHOD: sqlite3_changeset_iter
  **
  ** For each modified table, a changeset includes the following:
  **
  ** <ul>
  **   <li> The number of columns in the table, and
  **   <li> Which of those columns make up the tables PRIMARY KEY.
  ** </ul>
  **
  ** This function is used to find which columns comprise the PRIMARY KEY of
  ** the table modified by the change that iterator pIter currently points to.
  ** If successful, *pabPK is set to point to an array of nCol entries, where
  ** nCol is the number of columns in the table. Elements of *pabPK are set to
  ** 0x01 if the corresponding column is part of the tables primary key, or
  ** 0x00 if it is not.
  **
  ** If argument pnCol is not NULL, then *pnCol is set to the number of columns
  ** in the table.
  **
  ** If this function is called when the iterator does not point to a valid
  ** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
  ** SQLITE_OK is returned and the output variables populated as described
  ** above.
  */
  SQLITE_API int sqlite3changeset_pk(
    sqlite3_changeset_iter *pIter,  /* Iterator object */
    unsigned char **pabPK,          /* OUT: Array of boolean - true for PK cols */
    int *pnCol                      /* OUT: Number of entries in output array */
  );
  
  /*
  ** CAPI3REF: Obtain old.* Values From A Changeset Iterator
  ** METHOD: sqlite3_changeset_iter
  **
  ** The pIter argument passed to this function may either be an iterator
  ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
  ** created by [sqlite3changeset_start()]. In the latter case, the most recent
  ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
  ** Furthermore, it may only be called if the type of change that the iterator
  ** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
  ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
  **
  ** Argument iVal must be greater than or equal to 0, and less than the number
  ** of columns in the table affected by the current change. Otherwise,
  ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
  **
  ** If successful, this function sets *ppValue to point to a protected
  ** sqlite3_value object containing the iVal'th value from the vector of
  ** original row values stored as part of the UPDATE or DELETE change and
  ** returns SQLITE_OK. The name of the function comes from the fact that this
  ** is similar to the "old.*" columns available to update or delete triggers.
  **
  ** If some other error occurs (e.g. an OOM condition), an SQLite error code
  ** is returned and *ppValue is set to NULL.
  */
  SQLITE_API int sqlite3changeset_old(
    sqlite3_changeset_iter *pIter,  /* Changeset iterator */
    int iVal,                       /* Column number */
    sqlite3_value **ppValue         /* OUT: Old value (or NULL pointer) */
  );
  
  /*
  ** CAPI3REF: Obtain new.* Values From A Changeset Iterator
  ** METHOD: sqlite3_changeset_iter
  **
  ** The pIter argument passed to this function may either be an iterator
  ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
  ** created by [sqlite3changeset_start()]. In the latter case, the most recent
  ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
  ** Furthermore, it may only be called if the type of change that the iterator
  ** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
  ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
  **
  ** Argument iVal must be greater than or equal to 0, and less than the number
  ** of columns in the table affected by the current change. Otherwise,
  ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
  **
  ** If successful, this function sets *ppValue to point to a protected
  ** sqlite3_value object containing the iVal'th value from the vector of
  ** new row values stored as part of the UPDATE or INSERT change and
  ** returns SQLITE_OK. If the change is an UPDATE and does not include
  ** a new value for the requested column, *ppValue is set to NULL and
  ** SQLITE_OK returned. The name of the function comes from the fact that
  ** this is similar to the "new.*" columns available to update or delete
  ** triggers.
  **
  ** If some other error occurs (e.g. an OOM condition), an SQLite error code
  ** is returned and *ppValue is set to NULL.
  */
  SQLITE_API int sqlite3changeset_new(
    sqlite3_changeset_iter *pIter,  /* Changeset iterator */
    int iVal,                       /* Column number */
    sqlite3_value **ppValue         /* OUT: New value (or NULL pointer) */
  );
  
  /*
  ** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
  ** METHOD: sqlite3_changeset_iter
  **
  ** This function should only be used with iterator objects passed to a
  ** conflict-handler callback by [sqlite3changeset_apply()] with either
  ** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
  ** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
  ** is set to NULL.
  **
  ** Argument iVal must be greater than or equal to 0, and less than the number
  ** of columns in the table affected by the current change. Otherwise,
  ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
  **
  ** If successful, this function sets *ppValue to point to a protected
  ** sqlite3_value object containing the iVal'th value from the
  ** "conflicting row" associated with the current conflict-handler callback
  ** and returns SQLITE_OK.
  **
  ** If some other error occurs (e.g. an OOM condition), an SQLite error code
  ** is returned and *ppValue is set to NULL.
  */
  SQLITE_API int sqlite3changeset_conflict(
    sqlite3_changeset_iter *pIter,  /* Changeset iterator */
    int iVal,                       /* Column number */
    sqlite3_value **ppValue         /* OUT: Value from conflicting row */
  );
  
  /*
  ** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
  ** METHOD: sqlite3_changeset_iter
  **
  ** This function may only be called with an iterator passed to an
  ** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
  ** it sets the output variable to the total number of known foreign key
  ** violations in the destination database and returns SQLITE_OK.
  **
  ** In all other cases this function returns SQLITE_MISUSE.
  */
  SQLITE_API int sqlite3changeset_fk_conflicts(
    sqlite3_changeset_iter *pIter,  /* Changeset iterator */
    int *pnOut                      /* OUT: Number of FK violations */
  );
  
  
  /*
  ** CAPI3REF: Finalize A Changeset Iterator
  ** METHOD: sqlite3_changeset_iter
  **
  ** This function is used to finalize an iterator allocated with
  ** [sqlite3changeset_start()].
  **
  ** This function should only be called on iterators created using the
  ** [sqlite3changeset_start()] function. If an application calls this
  ** function with an iterator passed to a conflict-handler by
  ** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
  ** call has no effect.
  **
  ** If an error was encountered within a call to an sqlite3changeset_xxx()
  ** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
  ** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
  ** to that error is returned by this function. Otherwise, SQLITE_OK is
  ** returned. This is to allow the following pattern (pseudo-code):
  **
  ** <pre>
  **   sqlite3changeset_start();
  **   while( SQLITE_ROW==sqlite3changeset_next() ){
  **     // Do something with change.
  **   }
  **   rc = sqlite3changeset_finalize();
  **   if( rc!=SQLITE_OK ){
  **     // An error has occurred
  **   }
  ** </pre>
  */
  SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
  
  /*
  ** CAPI3REF: Invert A Changeset
  **
  ** This function is used to "invert" a changeset object. Applying an inverted
  ** changeset to a database reverses the effects of applying the uninverted
  ** changeset. Specifically:
  **
  ** <ul>
  **   <li> Each DELETE change is changed to an INSERT, and
  **   <li> Each INSERT change is changed to a DELETE, and
  **   <li> For each UPDATE change, the old.* and new.* values are exchanged.
  ** </ul>
  **
  ** This function does not change the order in which changes appear within
  ** the changeset. It merely reverses the sense of each individual change.
  **
  ** If successful, a pointer to a buffer containing the inverted changeset
  ** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
  ** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
  ** zeroed and an SQLite error code returned.
  **
  ** It is the responsibility of the caller to eventually call sqlite3_free()
  ** on the *ppOut pointer to free the buffer allocation following a successful
  ** call to this function.
  **
  ** WARNING/TODO: This function currently assumes that the input is a valid
  ** changeset. If it is not, the results are undefined.
  */
  SQLITE_API int sqlite3changeset_invert(
    int nIn, const void *pIn,       /* Input changeset */
    int *pnOut, void **ppOut        /* OUT: Inverse of input */
  );
  
  /*
  ** CAPI3REF: Concatenate Two Changeset Objects
  **
  ** This function is used to concatenate two changesets, A and B, into a
  ** single changeset. The result is a changeset equivalent to applying
  ** changeset A followed by changeset B.
  **
  ** This function combines the two input changesets using an
  ** sqlite3_changegroup object. Calling it produces similar results as the
  ** following code fragment:
  **
  ** <pre>
  **   sqlite3_changegroup *pGrp;
  **   rc = sqlite3_changegroup_new(&pGrp);
  **   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
  **   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
  **   if( rc==SQLITE_OK ){
  **     rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
  **   }else{
  **     *ppOut = 0;
  **     *pnOut = 0;
  **   }
  ** </pre>
  **
  ** Refer to the sqlite3_changegroup documentation below for details.
  */
  SQLITE_API int sqlite3changeset_concat(
    int nA,                         /* Number of bytes in buffer pA */
    void *pA,                       /* Pointer to buffer containing changeset A */
    int nB,                         /* Number of bytes in buffer pB */
    void *pB,                       /* Pointer to buffer containing changeset B */
    int *pnOut,                     /* OUT: Number of bytes in output changeset */
    void **ppOut                    /* OUT: Buffer containing output changeset */
  );
  
  
  /*
  ** CAPI3REF: Changegroup Handle
  **
  ** A changegroup is an object used to combine two or more
  ** [changesets] or [patchsets]
  */
  typedef struct sqlite3_changegroup sqlite3_changegroup;
  
  /*
  ** CAPI3REF: Create A New Changegroup Object
  ** CONSTRUCTOR: sqlite3_changegroup
  **
  ** An sqlite3_changegroup object is used to combine two or more changesets
  ** (or patchsets) into a single changeset (or patchset). A single changegroup
  ** object may combine changesets or patchsets, but not both. The output is
  ** always in the same format as the input.
  **
  ** If successful, this function returns SQLITE_OK and populates (*pp) with
  ** a pointer to a new sqlite3_changegroup object before returning. The caller
  ** should eventually free the returned object using a call to
  ** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
  ** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
  **
  ** The usual usage pattern for an sqlite3_changegroup object is as follows:
  **
  ** <ul>
  **   <li> It is created using a call to sqlite3changegroup_new().
  **
  **   <li> Zero or more changesets (or patchsets) are added to the object
  **        by calling sqlite3changegroup_add().
  **
  **   <li> The result of combining all input changesets together is obtained
  **        by the application via a call to sqlite3changegroup_output().
  **
  **   <li> The object is deleted using a call to sqlite3changegroup_delete().
  ** </ul>
  **
  ** Any number of calls to add() and output() may be made between the calls to
  ** new() and delete(), and in any order.
  **
  ** As well as the regular sqlite3changegroup_add() and
  ** sqlite3changegroup_output() functions, also available are the streaming
  ** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
  */
  SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
  
  /*
  ** CAPI3REF: Add A Changeset To A Changegroup
  ** METHOD: sqlite3_changegroup
  **
  ** Add all changes within the changeset (or patchset) in buffer pData (size
  ** nData bytes) to the changegroup.
  **
  ** If the buffer contains a patchset, then all prior calls to this function
  ** on the same changegroup object must also have specified patchsets. Or, if
  ** the buffer contains a changeset, so must have the earlier calls to this
  ** function. Otherwise, SQLITE_ERROR is returned and no changes are added
  ** to the changegroup.
  **
  ** Rows within the changeset and changegroup are identified by the values in
  ** their PRIMARY KEY columns. A change in the changeset is considered to
  ** apply to the same row as a change already present in the changegroup if
  ** the two rows have the same primary key.
  **
  ** Changes to rows that do not already appear in the changegroup are
  ** simply copied into it. Or, if both the new changeset and the changegroup
  ** contain changes that apply to a single row, the final contents of the
  ** changegroup depends on the type of each change, as follows:
  **
  ** <table border=1 style="margin-left:8ex;margin-right:8ex">
  **   <tr><th style="white-space:pre">Existing Change  </th>
  **       <th style="white-space:pre">New Change       </th>
  **       <th>Output Change
  **   <tr><td>INSERT <td>INSERT <td>
  **       The new change is ignored. This case does not occur if the new
  **       changeset was recorded immediately after the changesets already
  **       added to the changegroup.
  **   <tr><td>INSERT <td>UPDATE <td>
  **       The INSERT change remains in the changegroup. The values in the
  **       INSERT change are modified as if the row was inserted by the
  **       existing change and then updated according to the new change.
  **   <tr><td>INSERT <td>DELETE <td>
  **       The existing INSERT is removed from the changegroup. The DELETE is
  **       not added.
  **   <tr><td>UPDATE <td>INSERT <td>
  **       The new change is ignored. This case does not occur if the new
  **       changeset was recorded immediately after the changesets already
  **       added to the changegroup.
  **   <tr><td>UPDATE <td>UPDATE <td>
  **       The existing UPDATE remains within the changegroup. It is amended
  **       so that the accompanying values are as if the row was updated once
  **       by the existing change and then again by the new change.
  **   <tr><td>UPDATE <td>DELETE <td>
  **       The existing UPDATE is replaced by the new DELETE within the
  **       changegroup.
  **   <tr><td>DELETE <td>INSERT <td>
  **       If one or more of the column values in the row inserted by the
  **       new change differ from those in the row deleted by the existing
  **       change, the existing DELETE is replaced by an UPDATE within the
  **       changegroup. Otherwise, if the inserted row is exactly the same
  **       as the deleted row, the existing DELETE is simply discarded.
  **   <tr><td>DELETE <td>UPDATE <td>
  **       The new change is ignored. This case does not occur if the new
  **       changeset was recorded immediately after the changesets already
  **       added to the changegroup.
  **   <tr><td>DELETE <td>DELETE <td>
  **       The new change is ignored. This case does not occur if the new
  **       changeset was recorded immediately after the changesets already
  **       added to the changegroup.
  ** </table>
  **
  ** If the new changeset contains changes to a table that is already present
  ** in the changegroup, then the number of columns and the position of the
  ** primary key columns for the table must be consistent. If this is not the
  ** case, this function fails with SQLITE_SCHEMA. If the input changeset
  ** appears to be corrupt and the corruption is detected, SQLITE_CORRUPT is
  ** returned. Or, if an out-of-memory condition occurs during processing, this
  ** function returns SQLITE_NOMEM. In all cases, if an error occurs the state
  ** of the final contents of the changegroup is undefined.
  **
  ** If no error occurs, SQLITE_OK is returned.
  */
  SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
  
  /*
  ** CAPI3REF: Obtain A Composite Changeset From A Changegroup
  ** METHOD: sqlite3_changegroup
  **
  ** Obtain a buffer containing a changeset (or patchset) representing the
  ** current contents of the changegroup. If the inputs to the changegroup
  ** were themselves changesets, the output is a changeset. Or, if the
  ** inputs were patchsets, the output is also a patchset.
  **
  ** As with the output of the sqlite3session_changeset() and
  ** sqlite3session_patchset() functions, all changes related to a single
  ** table are grouped together in the output of this function. Tables appear
  ** in the same order as for the very first changeset added to the changegroup.
  ** If the second or subsequent changesets added to the changegroup contain
  ** changes for tables that do not appear in the first changeset, they are
  ** appended onto the end of the output changeset, again in the order in
  ** which they are first encountered.
  **
  ** If an error occurs, an SQLite error code is returned and the output
  ** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
  ** is returned and the output variables are set to the size of and a
  ** pointer to the output buffer, respectively. In this case it is the
  ** responsibility of the caller to eventually free the buffer using a
  ** call to sqlite3_free().
  */
  SQLITE_API int sqlite3changegroup_output(
    sqlite3_changegroup*,
    int *pnData,                    /* OUT: Size of output buffer in bytes */
    void **ppData                   /* OUT: Pointer to output buffer */
  );
  
  /*
  ** CAPI3REF: Delete A Changegroup Object
  ** DESTRUCTOR: sqlite3_changegroup
  */
  SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
  
  /*
  ** CAPI3REF: Apply A Changeset To A Database
  **
  ** Apply a changeset or patchset to a database. These functions attempt to
  ** update the "main" database attached to handle db with the changes found in
  ** the changeset passed via the second and third arguments.
  **
  ** The fourth argument (xFilter) passed to these functions is the "filter
  ** callback". If it is not NULL, then for each table affected by at least one
  ** change in the changeset, the filter callback is invoked with
  ** the table name as the second argument, and a copy of the context pointer
  ** passed as the sixth argument as the first. If the "filter callback"
  ** returns zero, then no attempt is made to apply any changes to the table.
  ** Otherwise, if the return value is non-zero or the xFilter argument to
  ** is NULL, all changes related to the table are attempted.
  **
  ** For each table that is not excluded by the filter callback, this function
  ** tests that the target database contains a compatible table. A table is
  ** considered compatible if all of the following are true:
  **
  ** <ul>
  **   <li> The table has the same name as the name recorded in the
  **        changeset, and
  **   <li> The table has at least as many columns as recorded in the
  **        changeset, and
  **   <li> The table has primary key columns in the same position as
  **        recorded in the changeset.
  ** </ul>
  **
  ** If there is no compatible table, it is not an error, but none of the
  ** changes associated with the table are applied. A warning message is issued
  ** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
  ** one such warning is issued for each table in the changeset.
  **
  ** For each change for which there is a compatible table, an attempt is made
  ** to modify the table contents according to the UPDATE, INSERT or DELETE
  ** change. If a change cannot be applied cleanly, the conflict handler
  ** function passed as the fifth argument to sqlite3changeset_apply() may be
  ** invoked. A description of exactly when the conflict handler is invoked for
  ** each type of change is below.
  **
  ** Unlike the xFilter argument, xConflict may not be passed NULL. The results
  ** of passing anything other than a valid function pointer as the xConflict
  ** argument are undefined.
  **
  ** Each time the conflict handler function is invoked, it must return one
  ** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
  ** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
  ** if the second argument passed to the conflict handler is either
  ** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
  ** returns an illegal value, any changes already made are rolled back and
  ** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
  ** actions are taken by sqlite3changeset_apply() depending on the value
  ** returned by each invocation of the conflict-handler function. Refer to
  ** the documentation for the three
  ** [SQLITE_CHANGESET_OMIT|available return values] for details.
  **
  ** <dl>
  ** <dt>DELETE Changes<dd>
  **   For each DELETE change, the function checks if the target database
  **   contains a row with the same primary key value (or values) as the
  **   original row values stored in the changeset. If it does, and the values
  **   stored in all non-primary key columns also match the values stored in
  **   the changeset the row is deleted from the target database.
  **
  **   If a row with matching primary key values is found, but one or more of
  **   the non-primary key fields contains a value different from the original
  **   row value stored in the changeset, the conflict-handler function is
  **   invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
  **   database table has more columns than are recorded in the changeset,
  **   only the values of those non-primary key fields are compared against
  **   the current database contents - any trailing database table columns
  **   are ignored.
  **
  **   If no row with matching primary key values is found in the database,
  **   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
  **   passed as the second argument.
  **
  **   If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
  **   (which can only happen if a foreign key constraint is violated), the
  **   conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
  **   passed as the second argument. This includes the case where the DELETE
  **   operation is attempted because an earlier call to the conflict handler
  **   function returned [SQLITE_CHANGESET_REPLACE].
  **
  ** <dt>INSERT Changes<dd>
  **   For each INSERT change, an attempt is made to insert the new row into
  **   the database. If the changeset row contains fewer fields than the
  **   database table, the trailing fields are populated with their default
  **   values.
  **
  **   If the attempt to insert the row fails because the database already
  **   contains a row with the same primary key values, the conflict handler
  **   function is invoked with the second argument set to
  **   [SQLITE_CHANGESET_CONFLICT].
  **
  **   If the attempt to insert the row fails because of some other constraint
  **   violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
  **   invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
  **   This includes the case where the INSERT operation is re-attempted because
  **   an earlier call to the conflict handler function returned
  **   [SQLITE_CHANGESET_REPLACE].
  **
  ** <dt>UPDATE Changes<dd>
  **   For each UPDATE change, the function checks if the target database
  **   contains a row with the same primary key value (or values) as the
  **   original row values stored in the changeset. If it does, and the values
  **   stored in all modified non-primary key columns also match the values
  **   stored in the changeset the row is updated within the target database.
  **
  **   If a row with matching primary key values is found, but one or more of
  **   the modified non-primary key fields contains a value different from an
  **   original row value stored in the changeset, the conflict-handler function
  **   is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
  **   UPDATE changes only contain values for non-primary key fields that are
  **   to be modified, only those fields need to match the original values to
  **   avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
  **
  **   If no row with matching primary key values is found in the database,
  **   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
  **   passed as the second argument.
  **
  **   If the UPDATE operation is attempted, but SQLite returns
  **   SQLITE_CONSTRAINT, the conflict-handler function is invoked with
  **   [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
  **   This includes the case where the UPDATE operation is attempted after
  **   an earlier call to the conflict handler function returned
  **   [SQLITE_CHANGESET_REPLACE].
  ** </dl>
  **
  ** It is safe to execute SQL statements, including those that write to the
  ** table that the callback related to, from within the xConflict callback.
  ** This can be used to further customize the application's conflict
  ** resolution strategy.
  **
  ** All changes made by these functions are enclosed in a savepoint transaction.
  ** If any other error (aside from a constraint failure when attempting to
  ** write to the target database) occurs, then the savepoint transaction is
  ** rolled back, restoring the target database to its original state, and an
  ** SQLite error code returned.
  **
  ** If the output parameters (ppRebase) and (pnRebase) are non-NULL and
  ** the input is a changeset (not a patchset), then sqlite3changeset_apply_v2()
  ** may set (*ppRebase) to point to a "rebase" that may be used with the
  ** sqlite3_rebaser APIs buffer before returning. In this case (*pnRebase)
  ** is set to the size of the buffer in bytes. It is the responsibility of the
  ** caller to eventually free any such buffer using sqlite3_free(). The buffer
  ** is only allocated and populated if one or more conflicts were encountered
  ** while applying the patchset. See comments surrounding the sqlite3_rebaser
  ** APIs for further details.
  **
  ** The behavior of sqlite3changeset_apply_v2() and its streaming equivalent
  ** may be modified by passing a combination of
  ** [SQLITE_CHANGESETAPPLY_NOSAVEPOINT | supported flags] as the 9th parameter.
  **
  ** Note that the sqlite3changeset_apply_v2() API is still <b>experimental</b>
  ** and therefore subject to change.
  */
  SQLITE_API int sqlite3changeset_apply(
    sqlite3 *db,                    /* Apply change to "main" db of this handle */
    int nChangeset,                 /* Size of changeset in bytes */
    void *pChangeset,               /* Changeset blob */
    int(*xFilter)(
      void *pCtx,                   /* Copy of sixth arg to _apply() */
      const char *zTab              /* Table name */
    ),
    int(*xConflict)(
      void *pCtx,                   /* Copy of sixth arg to _apply() */
      int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
      sqlite3_changeset_iter *p     /* Handle describing change and conflict */
    ),
    void *pCtx                      /* First argument passed to xConflict */
  );
  SQLITE_API int sqlite3changeset_apply_v2(
    sqlite3 *db,                    /* Apply change to "main" db of this handle */
    int nChangeset,                 /* Size of changeset in bytes */
    void *pChangeset,               /* Changeset blob */
    int(*xFilter)(
      void *pCtx,                   /* Copy of sixth arg to _apply() */
      const char *zTab              /* Table name */
    ),
    int(*xConflict)(
      void *pCtx,                   /* Copy of sixth arg to _apply() */
      int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
      sqlite3_changeset_iter *p     /* Handle describing change and conflict */
    ),
    void *pCtx,                     /* First argument passed to xConflict */
    void **ppRebase, int *pnRebase, /* OUT: Rebase data */
    int flags                       /* SESSION_CHANGESETAPPLY_* flags */
  );
  
  /*
  ** CAPI3REF: Flags for sqlite3changeset_apply_v2
  **
  ** The following flags may passed via the 9th parameter to
  ** [sqlite3changeset_apply_v2] and [sqlite3changeset_apply_v2_strm]:
  **
  ** <dl>
  ** <dt>SQLITE_CHANGESETAPPLY_NOSAVEPOINT <dd>
  **   Usually, the sessions module encloses all operations performed by
  **   a single call to apply_v2() or apply_v2_strm() in a [SAVEPOINT]. The
  **   SAVEPOINT is committed if the changeset or patchset is successfully
  **   applied, or rolled back if an error occurs. Specifying this flag
  **   causes the sessions module to omit this savepoint. In this case, if the
  **   caller has an open transaction or savepoint when apply_v2() is called,
  **   it may revert the partially applied changeset by rolling it back.
  **
  ** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
  **   Invert the changeset before applying it. This is equivalent to inverting
  **   a changeset using sqlite3changeset_invert() before applying it. It is
  **   an error to specify this flag with a patchset.
  */
  #define SQLITE_CHANGESETAPPLY_NOSAVEPOINT   0x0001
  #define SQLITE_CHANGESETAPPLY_INVERT        0x0002
  
  /*
  ** CAPI3REF: Constants Passed To The Conflict Handler
  **
  ** Values that may be passed as the second argument to a conflict-handler.
  **
  ** <dl>
  ** <dt>SQLITE_CHANGESET_DATA<dd>
  **   The conflict handler is invoked with CHANGESET_DATA as the second argument
  **   when processing a DELETE or UPDATE change if a row with the required
  **   PRIMARY KEY fields is present in the database, but one or more other
  **   (non primary-key) fields modified by the update do not contain the
  **   expected "before" values.
  **
  **   The conflicting row, in this case, is the database row with the matching
  **   primary key.
  **
  ** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
  **   The conflict handler is invoked with CHANGESET_NOTFOUND as the second
  **   argument when processing a DELETE or UPDATE change if a row with the
  **   required PRIMARY KEY fields is not present in the database.
  **
  **   There is no conflicting row in this case. The results of invoking the
  **   sqlite3changeset_conflict() API are undefined.
  **
  ** <dt>SQLITE_CHANGESET_CONFLICT<dd>
  **   CHANGESET_CONFLICT is passed as the second argument to the conflict
  **   handler while processing an INSERT change if the operation would result
  **   in duplicate primary key values.
  **
  **   The conflicting row in this case is the database row with the matching
  **   primary key.
  **
  ** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
  **   If foreign key handling is enabled, and applying a changeset leaves the
  **   database in a state containing foreign key violations, the conflict
  **   handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
  **   exactly once before the changeset is committed. If the conflict handler
  **   returns CHANGESET_OMIT, the changes, including those that caused the
  **   foreign key constraint violation, are committed. Or, if it returns
  **   CHANGESET_ABORT, the changeset is rolled back.
  **
  **   No current or conflicting row information is provided. The only function
  **   it is possible to call on the supplied sqlite3_changeset_iter handle
  **   is sqlite3changeset_fk_conflicts().
  **
  ** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
  **   If any other constraint violation occurs while applying a change (i.e.
  **   a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
  **   invoked with CHANGESET_CONSTRAINT as the second argument.
  **
  **   There is no conflicting row in this case. The results of invoking the
  **   sqlite3changeset_conflict() API are undefined.
  **
  ** </dl>
  */
  #define SQLITE_CHANGESET_DATA        1
  #define SQLITE_CHANGESET_NOTFOUND    2
  #define SQLITE_CHANGESET_CONFLICT    3
  #define SQLITE_CHANGESET_CONSTRAINT  4
  #define SQLITE_CHANGESET_FOREIGN_KEY 5
  
  /*
  ** CAPI3REF: Constants Returned By The Conflict Handler
  **
  ** A conflict handler callback must return one of the following three values.
  **
  ** <dl>
  ** <dt>SQLITE_CHANGESET_OMIT<dd>
  **   If a conflict handler returns this value no special action is taken. The
  **   change that caused the conflict is not applied. The session module
  **   continues to the next change in the changeset.
  **
  ** <dt>SQLITE_CHANGESET_REPLACE<dd>
  **   This value may only be returned if the second argument to the conflict
  **   handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
  **   is not the case, any changes applied so far are rolled back and the
  **   call to sqlite3changeset_apply() returns SQLITE_MISUSE.
  **
  **   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
  **   handler, then the conflicting row is either updated or deleted, depending
  **   on the type of change.
  **
  **   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
  **   handler, then the conflicting row is removed from the database and a
  **   second attempt to apply the change is made. If this second attempt fails,
  **   the original row is restored to the database before continuing.
  **
  ** <dt>SQLITE_CHANGESET_ABORT<dd>
  **   If this value is returned, any changes applied so far are rolled back
  **   and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
  ** </dl>
  */
  #define SQLITE_CHANGESET_OMIT       0
  #define SQLITE_CHANGESET_REPLACE    1
  #define SQLITE_CHANGESET_ABORT      2
  
  /*
  ** CAPI3REF: Rebasing changesets
  ** EXPERIMENTAL
  **
  ** Suppose there is a site hosting a database in state S0. And that
  ** modifications are made that move that database to state S1 and a
  ** changeset recorded (the "local" changeset). Then, a changeset based
  ** on S0 is received from another site (the "remote" changeset) and
  ** applied to the database. The database is then in state
  ** (S1+"remote"), where the exact state depends on any conflict
  ** resolution decisions (OMIT or REPLACE) made while applying "remote".
  ** Rebasing a changeset is to update it to take those conflict
  ** resolution decisions into account, so that the same conflicts
  ** do not have to be resolved elsewhere in the network.
  **
  ** For example, if both the local and remote changesets contain an
  ** INSERT of the same key on "CREATE TABLE t1(a PRIMARY KEY, b)":
  **
  **   local:  INSERT INTO t1 VALUES(1, 'v1');
  **   remote: INSERT INTO t1 VALUES(1, 'v2');
  **
  ** and the conflict resolution is REPLACE, then the INSERT change is
  ** removed from the local changeset (it was overridden). Or, if the
  ** conflict resolution was "OMIT", then the local changeset is modified
  ** to instead contain:
  **
  **           UPDATE t1 SET b = 'v2' WHERE a=1;
  **
  ** Changes within the local changeset are rebased as follows:
  **
  ** <dl>
  ** <dt>Local INSERT<dd>
  **   This may only conflict with a remote INSERT. If the conflict
  **   resolution was OMIT, then add an UPDATE change to the rebased
  **   changeset. Or, if the conflict resolution was REPLACE, add
  **   nothing to the rebased changeset.
  **
  ** <dt>Local DELETE<dd>
  **   This may conflict with a remote UPDATE or DELETE. In both cases the
  **   only possible resolution is OMIT. If the remote operation was a
  **   DELETE, then add no change to the rebased changeset. If the remote
  **   operation was an UPDATE, then the old.* fields of change are updated
  **   to reflect the new.* values in the UPDATE.
  **
  ** <dt>Local UPDATE<dd>
  **   This may conflict with a remote UPDATE or DELETE. If it conflicts
  **   with a DELETE, and the conflict resolution was OMIT, then the update
  **   is changed into an INSERT. Any undefined values in the new.* record
  **   from the update change are filled in using the old.* values from
  **   the conflicting DELETE. Or, if the conflict resolution was REPLACE,
  **   the UPDATE change is simply omitted from the rebased changeset.
  **
  **   If conflict is with a remote UPDATE and the resolution is OMIT, then
  **   the old.* values are rebased using the new.* values in the remote
  **   change. Or, if the resolution is REPLACE, then the change is copied
  **   into the rebased changeset with updates to columns also updated by
  **   the conflicting remote UPDATE removed. If this means no columns would
  **   be updated, the change is omitted.
  ** </dl>
  **
  ** A local change may be rebased against multiple remote changes
  ** simultaneously. If a single key is modified by multiple remote
  ** changesets, they are combined as follows before the local changeset
  ** is rebased:
  **
  ** <ul>
  **    <li> If there has been one or more REPLACE resolutions on a
  **         key, it is rebased according to a REPLACE.
  **
  **    <li> If there have been no REPLACE resolutions on a key, then
  **         the local changeset is rebased according to the most recent
  **         of the OMIT resolutions.
  ** </ul>
  **
  ** Note that conflict resolutions from multiple remote changesets are
  ** combined on a per-field basis, not per-row. This means that in the
  ** case of multiple remote UPDATE operations, some fields of a single
  ** local change may be rebased for REPLACE while others are rebased for
  ** OMIT.
  **
  ** In order to rebase a local changeset, the remote changeset must first
  ** be applied to the local database using sqlite3changeset_apply_v2() and
  ** the buffer of rebase information captured. Then:
  **
  ** <ol>
  **   <li> An sqlite3_rebaser object is created by calling
  **        sqlite3rebaser_create().
  **   <li> The new object is configured with the rebase buffer obtained from
  **        sqlite3changeset_apply_v2() by calling sqlite3rebaser_configure().
  **        If the local changeset is to be rebased against multiple remote
  **        changesets, then sqlite3rebaser_configure() should be called
  **        multiple times, in the same order that the multiple
  **        sqlite3changeset_apply_v2() calls were made.
  **   <li> Each local changeset is rebased by calling sqlite3rebaser_rebase().
  **   <li> The sqlite3_rebaser object is deleted by calling
  **        sqlite3rebaser_delete().
  ** </ol>
  */
  typedef struct sqlite3_rebaser sqlite3_rebaser;
  
  /*
  ** CAPI3REF: Create a changeset rebaser object.
  ** EXPERIMENTAL
  **
  ** Allocate a new changeset rebaser object. If successful, set (*ppNew) to
  ** point to the new object and return SQLITE_OK. Otherwise, if an error
  ** occurs, return an SQLite error code (e.g. SQLITE_NOMEM) and set (*ppNew)
  ** to NULL.
  */
  SQLITE_API int sqlite3rebaser_create(sqlite3_rebaser **ppNew);
  
  /*
  ** CAPI3REF: Configure a changeset rebaser object.
  ** EXPERIMENTAL
  **
  ** Configure the changeset rebaser object to rebase changesets according
  ** to the conflict resolutions described by buffer pRebase (size nRebase
  ** bytes), which must have been obtained from a previous call to
  ** sqlite3changeset_apply_v2().
  */
  SQLITE_API int sqlite3rebaser_configure(
    sqlite3_rebaser*,
    int nRebase, const void *pRebase
  );
  
  /*
  ** CAPI3REF: Rebase a changeset
  ** EXPERIMENTAL
  **
  ** Argument pIn must point to a buffer containing a changeset nIn bytes
  ** in size. This function allocates and populates a buffer with a copy
  ** of the changeset rebased according to the configuration of the
  ** rebaser object passed as the first argument. If successful, (*ppOut)
  ** is set to point to the new buffer containing the rebased changeset and
  ** (*pnOut) to its size in bytes and SQLITE_OK returned. It is the
  ** responsibility of the caller to eventually free the new buffer using
  ** sqlite3_free(). Otherwise, if an error occurs, (*ppOut) and (*pnOut)
  ** are set to zero and an SQLite error code returned.
  */
  SQLITE_API int sqlite3rebaser_rebase(
    sqlite3_rebaser*,
    int nIn, const void *pIn,
    int *pnOut, void **ppOut
  );
  
  /*
  ** CAPI3REF: Delete a changeset rebaser object.
  ** EXPERIMENTAL
  **
  ** Delete the changeset rebaser object and all associated resources. There
  ** should be one call to this function for each successful invocation
  ** of sqlite3rebaser_create().
  */
  SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p);
  
  /*
  ** CAPI3REF: Streaming Versions of API functions.
  **
  ** The six streaming API xxx_strm() functions serve similar purposes to the
  ** corresponding non-streaming API functions:
  **
  ** <table border=1 style="margin-left:8ex;margin-right:8ex">
  **   <tr><th>Streaming function<th>Non-streaming equivalent</th>
  **   <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
  **   <tr><td>sqlite3changeset_apply_strm_v2<td>[sqlite3changeset_apply_v2]
  **   <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
  **   <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
  **   <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
  **   <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
  **   <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
  ** </table>
  **
  ** Non-streaming functions that accept changesets (or patchsets) as input
  ** require that the entire changeset be stored in a single buffer in memory.
  ** Similarly, those that return a changeset or patchset do so by returning
  ** a pointer to a single large buffer allocated using sqlite3_malloc().
  ** Normally this is convenient. However, if an application running in a
  ** low-memory environment is required to handle very large changesets, the
  ** large contiguous memory allocations required can become onerous.
  **
  ** In order to avoid this problem, instead of a single large buffer, input
  ** is passed to a streaming API functions by way of a callback function that
  ** the sessions module invokes to incrementally request input data as it is
  ** required. In all cases, a pair of API function parameters such as
  **
  **  <pre>
  **  &nbsp;     int nChangeset,
  **  &nbsp;     void *pChangeset,
  **  </pre>
  **
  ** Is replaced by:
  **
  **  <pre>
  **  &nbsp;     int (*xInput)(void *pIn, void *pData, int *pnData),
  **  &nbsp;     void *pIn,
  **  </pre>
  **
  ** Each time the xInput callback is invoked by the sessions module, the first
  ** argument passed is a copy of the supplied pIn context pointer. The second
  ** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
  ** error occurs the xInput method should copy up to (*pnData) bytes of data
  ** into the buffer and set (*pnData) to the actual number of bytes copied
  ** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
  ** should be set to zero to indicate this. Or, if an error occurs, an SQLite
  ** error code should be returned. In all cases, if an xInput callback returns
  ** an error, all processing is abandoned and the streaming API function
  ** returns a copy of the error code to the caller.
  **
  ** In the case of sqlite3changeset_start_strm(), the xInput callback may be
  ** invoked by the sessions module at any point during the lifetime of the
  ** iterator. If such an xInput callback returns an error, the iterator enters
  ** an error state, whereby all subsequent calls to iterator functions
  ** immediately fail with the same error code as returned by xInput.
  **
  ** Similarly, streaming API functions that return changesets (or patchsets)
  ** return them in chunks by way of a callback function instead of via a
  ** pointer to a single large buffer. In this case, a pair of parameters such
  ** as:
  **
  **  <pre>
  **  &nbsp;     int *pnChangeset,
  **  &nbsp;     void **ppChangeset,
  **  </pre>
  **
  ** Is replaced by:
  **
  **  <pre>
  **  &nbsp;     int (*xOutput)(void *pOut, const void *pData, int nData),
  **  &nbsp;     void *pOut
  **  </pre>
  **
  ** The xOutput callback is invoked zero or more times to return data to
  ** the application. The first parameter passed to each call is a copy of the
  ** pOut pointer supplied by the application. The second parameter, pData,
  ** points to a buffer nData bytes in size containing the chunk of output
  ** data being returned. If the xOutput callback successfully processes the
  ** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
  ** it should return some other SQLite error code. In this case processing
  ** is immediately abandoned and the streaming API function returns a copy
  ** of the xOutput error code to the application.
  **
  ** The sessions module never invokes an xOutput callback with the third
  ** parameter set to a value less than or equal to zero. Other than this,
  ** no guarantees are made as to the size of the chunks of data returned.
  */
  SQLITE_API int sqlite3changeset_apply_strm(
    sqlite3 *db,                    /* Apply change to "main" db of this handle */
    int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
    void *pIn,                                          /* First arg for xInput */
    int(*xFilter)(
      void *pCtx,                   /* Copy of sixth arg to _apply() */
      const char *zTab              /* Table name */
    ),
    int(*xConflict)(
      void *pCtx,                   /* Copy of sixth arg to _apply() */
      int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
      sqlite3_changeset_iter *p     /* Handle describing change and conflict */
    ),
    void *pCtx                      /* First argument passed to xConflict */
  );
  SQLITE_API int sqlite3changeset_apply_v2_strm(
    sqlite3 *db,                    /* Apply change to "main" db of this handle */
    int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
    void *pIn,                                          /* First arg for xInput */
    int(*xFilter)(
      void *pCtx,                   /* Copy of sixth arg to _apply() */
      const char *zTab              /* Table name */
    ),
    int(*xConflict)(
      void *pCtx,                   /* Copy of sixth arg to _apply() */
      int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
      sqlite3_changeset_iter *p     /* Handle describing change and conflict */
    ),
    void *pCtx,                     /* First argument passed to xConflict */
    void **ppRebase, int *pnRebase,
    int flags
  );
  SQLITE_API int sqlite3changeset_concat_strm(
    int (*xInputA)(void *pIn, void *pData, int *pnData),
    void *pInA,
    int (*xInputB)(void *pIn, void *pData, int *pnData),
    void *pInB,
    int (*xOutput)(void *pOut, const void *pData, int nData),
    void *pOut
  );
  SQLITE_API int sqlite3changeset_invert_strm(
    int (*xInput)(void *pIn, void *pData, int *pnData),
    void *pIn,
    int (*xOutput)(void *pOut, const void *pData, int nData),
    void *pOut
  );
  SQLITE_API int sqlite3changeset_start_strm(
    sqlite3_changeset_iter **pp,
    int (*xInput)(void *pIn, void *pData, int *pnData),
    void *pIn
  );
  SQLITE_API int sqlite3changeset_start_v2_strm(
    sqlite3_changeset_iter **pp,
    int (*xInput)(void *pIn, void *pData, int *pnData),
    void *pIn,
    int flags
  );
  SQLITE_API int sqlite3session_changeset_strm(
    sqlite3_session *pSession,
    int (*xOutput)(void *pOut, const void *pData, int nData),
    void *pOut
  );
  SQLITE_API int sqlite3session_patchset_strm(
    sqlite3_session *pSession,
    int (*xOutput)(void *pOut, const void *pData, int nData),
    void *pOut
  );
  SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*,
      int (*xInput)(void *pIn, void *pData, int *pnData),
      void *pIn
  );
  SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
      int (*xOutput)(void *pOut, const void *pData, int nData),
      void *pOut
  );
  SQLITE_API int sqlite3rebaser_rebase_strm(
    sqlite3_rebaser *pRebaser,
    int (*xInput)(void *pIn, void *pData, int *pnData),
    void *pIn,
    int (*xOutput)(void *pOut, const void *pData, int nData),
    void *pOut
  );
  
  /*
  ** CAPI3REF: Configure global parameters
  **
  ** The sqlite3session_config() interface is used to make global configuration
  ** changes to the sessions module in order to tune it to the specific needs
  ** of the application.
  **
  ** The sqlite3session_config() interface is not threadsafe. If it is invoked
  ** while any other thread is inside any other sessions method then the
  ** results are undefined. Furthermore, if it is invoked after any sessions
  ** related objects have been created, the results are also undefined.
  **
  ** The first argument to the sqlite3session_config() function must be one
  ** of the SQLITE_SESSION_CONFIG_XXX constants defined below. The
  ** interpretation of the (void*) value passed as the second parameter and
  ** the effect of calling this function depends on the value of the first
  ** parameter.
  **
  ** <dl>
  ** <dt>SQLITE_SESSION_CONFIG_STRMSIZE<dd>
  **    By default, the sessions module streaming interfaces attempt to input
  **    and output data in approximately 1 KiB chunks. This operand may be used
  **    to set and query the value of this configuration setting. The pointer
  **    passed as the second argument must point to a value of type (int).
  **    If this value is greater than 0, it is used as the new streaming data
  **    chunk size for both input and output. Before returning, the (int) value
  **    pointed to by pArg is set to the final value of the streaming interface
  **    chunk size.
  ** </dl>
  **
  ** This function returns SQLITE_OK if successful, or an SQLite error code
  ** otherwise.
  */
  SQLITE_API int sqlite3session_config(int op, void *pArg);
  
  /*
  ** CAPI3REF: Values for sqlite3session_config().
  */
  #define SQLITE_SESSION_CONFIG_STRMSIZE 1
  
  /*
  ** Make sure we can call this stuff from C++.
  */
  #ifdef __cplusplus
  }
  #endif
  
  #endif  /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
  
  /******** End of sqlite3session.h *********/
  /******** Begin file fts5.h *********/
  /*
  ** 2014 May 31
  **
  ** The author disclaims copyright to this source code.  In place of
  ** a legal notice, here is a blessing:
  **
  **    May you do good and not evil.
  **    May you find forgiveness for yourself and forgive others.
  **    May you share freely, never taking more than you give.
  **
  ******************************************************************************
  **
  ** Interfaces to extend FTS5. Using the interfaces defined in this file,
  ** FTS5 may be extended with:
  **
  **     * custom tokenizers, and
  **     * custom auxiliary functions.
  */
  
  
  #ifndef _FTS5_H
  #define _FTS5_H
  
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /*************************************************************************
  ** CUSTOM AUXILIARY FUNCTIONS
  **
  ** Virtual table implementations may overload SQL functions by implementing
  ** the sqlite3_module.xFindFunction() method.
  */
  
  typedef struct Fts5ExtensionApi Fts5ExtensionApi;
  typedef struct Fts5Context Fts5Context;
  typedef struct Fts5PhraseIter Fts5PhraseIter;
  
  typedef void (*fts5_extension_function)(
    const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
    Fts5Context *pFts,              /* First arg to pass to pApi functions */
    sqlite3_context *pCtx,          /* Context for returning result/error */
    int nVal,                       /* Number of values in apVal[] array */
    sqlite3_value **apVal           /* Array of trailing arguments */
  );
  
  struct Fts5PhraseIter {
    const unsigned char *a;
    const unsigned char *b;
  };
  
  /*
  ** EXTENSION API FUNCTIONS
  **
  ** xUserData(pFts):
  **   Return a copy of the context pointer the extension function was
  **   registered with.
  **
  ** xColumnTotalSize(pFts, iCol, pnToken):
  **   If parameter iCol is less than zero, set output variable *pnToken
  **   to the total number of tokens in the FTS5 table. Or, if iCol is
  **   non-negative but less than the number of columns in the table, return
  **   the total number of tokens in column iCol, considering all rows in
  **   the FTS5 table.
  **
  **   If parameter iCol is greater than or equal to the number of columns
  **   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
  **   an OOM condition or IO error), an appropriate SQLite error code is
  **   returned.
  **
  ** xColumnCount(pFts):
  **   Return the number of columns in the table.
  **
  ** xColumnSize(pFts, iCol, pnToken):
  **   If parameter iCol is less than zero, set output variable *pnToken
  **   to the total number of tokens in the current row. Or, if iCol is
  **   non-negative but less than the number of columns in the table, set
  **   *pnToken to the number of tokens in column iCol of the current row.
  **
  **   If parameter iCol is greater than or equal to the number of columns
  **   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
  **   an OOM condition or IO error), an appropriate SQLite error code is
  **   returned.
  **
  **   This function may be quite inefficient if used with an FTS5 table
  **   created with the "columnsize=0" option.
  **
  ** xColumnText:
  **   This function attempts to retrieve the text of column iCol of the
  **   current document. If successful, (*pz) is set to point to a buffer
  **   containing the text in utf-8 encoding, (*pn) is set to the size in bytes
  **   (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
  **   if an error occurs, an SQLite error code is returned and the final values
  **   of (*pz) and (*pn) are undefined.
  **
  ** xPhraseCount:
  **   Returns the number of phrases in the current query expression.
  **
  ** xPhraseSize:
  **   Returns the number of tokens in phrase iPhrase of the query. Phrases
  **   are numbered starting from zero.
  **
  ** xInstCount:
  **   Set *pnInst to the total number of occurrences of all phrases within
  **   the query within the current row. Return SQLITE_OK if successful, or
  **   an error code (i.e. SQLITE_NOMEM) if an error occurs.
  **
  **   This API can be quite slow if used with an FTS5 table created with the
  **   "detail=none" or "detail=column" option. If the FTS5 table is created
  **   with either "detail=none" or "detail=column" and "content=" option
  **   (i.e. if it is a contentless table), then this API always returns 0.
  **
  ** xInst:
  **   Query for the details of phrase match iIdx within the current row.
  **   Phrase matches are numbered starting from zero, so the iIdx argument
  **   should be greater than or equal to zero and smaller than the value
  **   output by xInstCount().
  **
  **   Usually, output parameter *piPhrase is set to the phrase number, *piCol
  **   to the column in which it occurs and *piOff the token offset of the
  **   first token of the phrase. Returns SQLITE_OK if successful, or an error
  **   code (i.e. SQLITE_NOMEM) if an error occurs.
  **
  **   This API can be quite slow if used with an FTS5 table created with the
  **   "detail=none" or "detail=column" option.
  **
  ** xRowid:
  **   Returns the rowid of the current row.
  **
  ** xTokenize:
  **   Tokenize text using the tokenizer belonging to the FTS5 table.
  **
  ** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
  **   This API function is used to query the FTS table for phrase iPhrase
  **   of the current query. Specifically, a query equivalent to:
  **
  **       ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
  **
  **   with $p set to a phrase equivalent to the phrase iPhrase of the
  **   current query is executed. Any column filter that applies to
  **   phrase iPhrase of the current query is included in $p. For each
  **   row visited, the callback function passed as the fourth argument
  **   is invoked. The context and API objects passed to the callback
  **   function may be used to access the properties of each matched row.
  **   Invoking Api.xUserData() returns a copy of the pointer passed as
  **   the third argument to pUserData.
  **
  **   If the callback function returns any value other than SQLITE_OK, the
  **   query is abandoned and the xQueryPhrase function returns immediately.
  **   If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
  **   Otherwise, the error code is propagated upwards.
  **
  **   If the query runs to completion without incident, SQLITE_OK is returned.
  **   Or, if some error occurs before the query completes or is aborted by
  **   the callback, an SQLite error code is returned.
  **
  **
  ** xSetAuxdata(pFts5, pAux, xDelete)
  **
  **   Save the pointer passed as the second argument as the extension function's
  **   "auxiliary data". The pointer may then be retrieved by the current or any
  **   future invocation of the same fts5 extension function made as part of
  **   the same MATCH query using the xGetAuxdata() API.
  **
  **   Each extension function is allocated a single auxiliary data slot for
  **   each FTS query (MATCH expression). If the extension function is invoked
  **   more than once for a single FTS query, then all invocations share a
  **   single auxiliary data context.
  **
  **   If there is already an auxiliary data pointer when this function is
  **   invoked, then it is replaced by the new pointer. If an xDelete callback
  **   was specified along with the original pointer, it is invoked at this
  **   point.
  **
  **   The xDelete callback, if one is specified, is also invoked on the
  **   auxiliary data pointer after the FTS5 query has finished.
  **
  **   If an error (e.g. an OOM condition) occurs within this function,
  **   the auxiliary data is set to NULL and an error code returned. If the
  **   xDelete parameter was not NULL, it is invoked on the auxiliary data
  **   pointer before returning.
  **
  **
  ** xGetAuxdata(pFts5, bClear)
  **
  **   Returns the current auxiliary data pointer for the fts5 extension
  **   function. See the xSetAuxdata() method for details.
  **
  **   If the bClear argument is non-zero, then the auxiliary data is cleared
  **   (set to NULL) before this function returns. In this case the xDelete,
  **   if any, is not invoked.
  **
  **
  ** xRowCount(pFts5, pnRow)
  **
  **   This function is used to retrieve the total number of rows in the table.
  **   In other words, the same value that would be returned by:
  **
  **        SELECT count(*) FROM ftstable;
  **
  ** xPhraseFirst()
  **   This function is used, along with type Fts5PhraseIter and the xPhraseNext
  **   method, to iterate through all instances of a single query phrase within
  **   the current row. This is the same information as is accessible via the
  **   xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
  **   to use, this API may be faster under some circumstances. To iterate
  **   through instances of phrase iPhrase, use the following code:
  **
  **       Fts5PhraseIter iter;
  **       int iCol, iOff;
  **       for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
  **           iCol>=0;
  **           pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
  **       ){
  **         // An instance of phrase iPhrase at offset iOff of column iCol
  **       }
  **
  **   The Fts5PhraseIter structure is defined above. Applications should not
  **   modify this structure directly - it should only be used as shown above
  **   with the xPhraseFirst() and xPhraseNext() API methods (and by
  **   xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
  **
  **   This API can be quite slow if used with an FTS5 table created with the
  **   "detail=none" or "detail=column" option. If the FTS5 table is created
  **   with either "detail=none" or "detail=column" and "content=" option
  **   (i.e. if it is a contentless table), then this API always iterates
  **   through an empty set (all calls to xPhraseFirst() set iCol to -1).
  **
  ** xPhraseNext()
  **   See xPhraseFirst above.
  **
  ** xPhraseFirstColumn()
  **   This function and xPhraseNextColumn() are similar to the xPhraseFirst()
  **   and xPhraseNext() APIs described above. The difference is that instead
  **   of iterating through all instances of a phrase in the current row, these
  **   APIs are used to iterate through the set of columns in the current row
  **   that contain one or more instances of a specified phrase. For example:
  **
  **       Fts5PhraseIter iter;
  **       int iCol;
  **       for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
  **           iCol>=0;
  **           pApi->xPhraseNextColumn(pFts, &iter, &iCol)
  **       ){
  **         // Column iCol contains at least one instance of phrase iPhrase
  **       }
  **
  **   This API can be quite slow if used with an FTS5 table created with the
  **   "detail=none" option. If the FTS5 table is created with either
  **   "detail=none" "content=" option (i.e. if it is a contentless table),
  **   then this API always iterates through an empty set (all calls to
  **   xPhraseFirstColumn() set iCol to -1).
  **
  **   The information accessed using this API and its companion
  **   xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
  **   (or xInst/xInstCount). The chief advantage of this API is that it is
  **   significantly more efficient than those alternatives when used with
  **   "detail=column" tables.
  **
  ** xPhraseNextColumn()
  **   See xPhraseFirstColumn above.
  */
  struct Fts5ExtensionApi {
    int iVersion;                   /* Currently always set to 3 */
  
    void *(*xUserData)(Fts5Context*);
  
    int (*xColumnCount)(Fts5Context*);
    int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
    int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
  
    int (*xTokenize)(Fts5Context*,
      const char *pText, int nText, /* Text to tokenize */
      void *pCtx,                   /* Context passed to xToken() */
      int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
    );
  
    int (*xPhraseCount)(Fts5Context*);
    int (*xPhraseSize)(Fts5Context*, int iPhrase);
  
    int (*xInstCount)(Fts5Context*, int *pnInst);
    int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
  
    sqlite3_int64 (*xRowid)(Fts5Context*);
    int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
    int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
  
    int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
      int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
    );
    int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
    void *(*xGetAuxdata)(Fts5Context*, int bClear);
  
    int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
    void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
  
    int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
    void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
  };
  
  /*
  ** CUSTOM AUXILIARY FUNCTIONS
  *************************************************************************/
  
  /*************************************************************************
  ** CUSTOM TOKENIZERS
  **
  ** Applications may also register custom tokenizer types. A tokenizer
  ** is registered by providing fts5 with a populated instance of the
  ** following structure. All structure methods must be defined, setting
  ** any member of the fts5_tokenizer struct to NULL leads to undefined
  ** behaviour. The structure methods are expected to function as follows:
  **
  ** xCreate:
  **   This function is used to allocate and initialize a tokenizer instance.
  **   A tokenizer instance is required to actually tokenize text.
  **
  **   The first argument passed to this function is a copy of the (void*)
  **   pointer provided by the application when the fts5_tokenizer object
  **   was registered with FTS5 (the third argument to xCreateTokenizer()).
  **   The second and third arguments are an array of nul-terminated strings
  **   containing the tokenizer arguments, if any, specified following the
  **   tokenizer name as part of the CREATE VIRTUAL TABLE statement used
  **   to create the FTS5 table.
  **
  **   The final argument is an output variable. If successful, (*ppOut)
  **   should be set to point to the new tokenizer handle and SQLITE_OK
  **   returned. If an error occurs, some value other than SQLITE_OK should
  **   be returned. In this case, fts5 assumes that the final value of *ppOut
  **   is undefined.
  **
  ** xDelete:
  **   This function is invoked to delete a tokenizer handle previously
  **   allocated using xCreate(). Fts5 guarantees that this function will
  **   be invoked exactly once for each successful call to xCreate().
  **
  ** xTokenize:
  **   This function is expected to tokenize the nText byte string indicated
  **   by argument pText. pText may or may not be nul-terminated. The first
  **   argument passed to this function is a pointer to an Fts5Tokenizer object
  **   returned by an earlier call to xCreate().
  **
  **   The second argument indicates the reason that FTS5 is requesting
  **   tokenization of the supplied text. This is always one of the following
  **   four values:
  **
  **   <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
  **            or removed from the FTS table. The tokenizer is being invoked to
  **            determine the set of tokens to add to (or delete from) the
  **            FTS index.
  **
  **       <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
  **            against the FTS index. The tokenizer is being called to tokenize
  **            a bareword or quoted string specified as part of the query.
  **
  **       <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
  **            FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
  **            followed by a "*" character, indicating that the last token
  **            returned by the tokenizer will be treated as a token prefix.
  **
  **       <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
  **            satisfy an fts5_api.xTokenize() request made by an auxiliary
  **            function. Or an fts5_api.xColumnSize() request made by the same
  **            on a columnsize=0 database.
  **   </ul>
  **
  **   For each token in the input string, the supplied callback xToken() must
  **   be invoked. The first argument to it should be a copy of the pointer
  **   passed as the second argument to xTokenize(). The third and fourth
  **   arguments are a pointer to a buffer containing the token text, and the
  **   size of the token in bytes. The 4th and 5th arguments are the byte offsets
  **   of the first byte of and first byte immediately following the text from
  **   which the token is derived within the input.
  **
  **   The second argument passed to the xToken() callback ("tflags") should
  **   normally be set to 0. The exception is if the tokenizer supports
  **   synonyms. In this case see the discussion below for details.
  **
  **   FTS5 assumes the xToken() callback is invoked for each token in the
  **   order that they occur within the input text.
  **
  **   If an xToken() callback returns any value other than SQLITE_OK, then
  **   the tokenization should be abandoned and the xTokenize() method should
  **   immediately return a copy of the xToken() return value. Or, if the
  **   input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
  **   if an error occurs with the xTokenize() implementation itself, it
  **   may abandon the tokenization and return any error code other than
  **   SQLITE_OK or SQLITE_DONE.
  **
  ** SYNONYM SUPPORT
  **
  **   Custom tokenizers may also support synonyms. Consider a case in which a
  **   user wishes to query for a phrase such as "first place". Using the
  **   built-in tokenizers, the FTS5 query 'first + place' will match instances
  **   of "first place" within the document set, but not alternative forms
  **   such as "1st place". In some applications, it would be better to match
  **   all instances of "first place" or "1st place" regardless of which form
  **   the user specified in the MATCH query text.
  **
  **   There are several ways to approach this in FTS5:
  **
  **   <ol><li> By mapping all synonyms to a single token. In this case, using
  **            the above example, this means that the tokenizer returns the
  **            same token for inputs "first" and "1st". Say that token is in
  **            fact "first", so that when the user inserts the document "I won
  **            1st place" entries are added to the index for tokens "i", "won",
  **            "first" and "place". If the user then queries for '1st + place',
  **            the tokenizer substitutes "first" for "1st" and the query works
  **            as expected.
  **
  **       <li> By querying the index for all synonyms of each query term
  **            separately. In this case, when tokenizing query text, the
  **            tokenizer may provide multiple synonyms for a single term
  **            within the document. FTS5 then queries the index for each
  **            synonym individually. For example, faced with the query:
  **
  **   <codeblock>
  **     ... MATCH 'first place'</codeblock>
  **
  **            the tokenizer offers both "1st" and "first" as synonyms for the
  **            first token in the MATCH query and FTS5 effectively runs a query
  **            similar to:
  **
  **   <codeblock>
  **     ... MATCH '(first OR 1st) place'</codeblock>
  **
  **            except that, for the purposes of auxiliary functions, the query
  **            still appears to contain just two phrases - "(first OR 1st)"
  **            being treated as a single phrase.
  **
  **       <li> By adding multiple synonyms for a single term to the FTS index.
  **            Using this method, when tokenizing document text, the tokenizer
  **            provides multiple synonyms for each token. So that when a
  **            document such as "I won first place" is tokenized, entries are
  **            added to the FTS index for "i", "won", "first", "1st" and
  **            "place".
  **
  **            This way, even if the tokenizer does not provide synonyms
  **            when tokenizing query text (it should not - to do so would be
  **            inefficient), it doesn't matter if the user queries for
  **            'first + place' or '1st + place', as there are entries in the
  **            FTS index corresponding to both forms of the first token.
  **   </ol>
  **
  **   Whether it is parsing document or query text, any call to xToken that
  **   specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
  **   is considered to supply a synonym for the previous token. For example,
  **   when parsing the document "I won first place", a tokenizer that supports
  **   synonyms would call xToken() 5 times, as follows:
  **
  **   <codeblock>
  **       xToken(pCtx, 0, "i",                      1,  0,  1);
  **       xToken(pCtx, 0, "won",                    3,  2,  5);
  **       xToken(pCtx, 0, "first",                  5,  6, 11);
  **       xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3,  6, 11);
  **       xToken(pCtx, 0, "place",                  5, 12, 17);
  **</codeblock>
  **
  **   It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
  **   xToken() is called. Multiple synonyms may be specified for a single token
  **   by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
  **   There is no limit to the number of synonyms that may be provided for a
  **   single token.
  **
  **   In many cases, method (1) above is the best approach. It does not add
  **   extra data to the FTS index or require FTS5 to query for multiple terms,
  **   so it is efficient in terms of disk space and query speed. However, it
  **   does not support prefix queries very well. If, as suggested above, the
  **   token "first" is substituted for "1st" by the tokenizer, then the query:
  **
  **   <codeblock>
  **     ... MATCH '1s*'</codeblock>
  **
  **   will not match documents that contain the token "1st" (as the tokenizer
  **   will probably not map "1s" to any prefix of "first").
  **
  **   For full prefix support, method (3) may be preferred. In this case,
  **   because the index contains entries for both "first" and "1st", prefix
  **   queries such as 'fi*' or '1s*' will match correctly. However, because
  **   extra entries are added to the FTS index, this method uses more space
  **   within the database.
  **
  **   Method (2) offers a midpoint between (1) and (3). Using this method,
  **   a query such as '1s*' will match documents that contain the literal
  **   token "1st", but not "first" (assuming the tokenizer is not able to
  **   provide synonyms for prefixes). However, a non-prefix query like '1st'
  **   will match against "1st" and "first". This method does not require
  **   extra disk space, as no extra entries are added to the FTS index.
  **   On the other hand, it may require more CPU cycles to run MATCH queries,
  **   as separate queries of the FTS index are required for each synonym.
  **
  **   When using methods (2) or (3), it is important that the tokenizer only
  **   provide synonyms when tokenizing document text (method (2)) or query
  **   text (method (3)), not both. Doing so will not cause any errors, but is
  **   inefficient.
  */
  typedef struct Fts5Tokenizer Fts5Tokenizer;
  typedef struct fts5_tokenizer fts5_tokenizer;
  struct fts5_tokenizer {
    int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
    void (*xDelete)(Fts5Tokenizer*);
    int (*xTokenize)(Fts5Tokenizer*,
        void *pCtx,
        int flags,            /* Mask of FTS5_TOKENIZE_* flags */
        const char *pText, int nText,
        int (*xToken)(
          void *pCtx,         /* Copy of 2nd argument to xTokenize() */
          int tflags,         /* Mask of FTS5_TOKEN_* flags */
          const char *pToken, /* Pointer to buffer containing token */
          int nToken,         /* Size of token in bytes */
          int iStart,         /* Byte offset of token within input text */
          int iEnd            /* Byte offset of end of token within input text */
        )
    );
  };
  
  /* Flags that may be passed as the third argument to xTokenize() */
  #define FTS5_TOKENIZE_QUERY     0x0001
  #define FTS5_TOKENIZE_PREFIX    0x0002
  #define FTS5_TOKENIZE_DOCUMENT  0x0004
  #define FTS5_TOKENIZE_AUX       0x0008
  
  /* Flags that may be passed by the tokenizer implementation back to FTS5
  ** as the third argument to the supplied xToken callback. */
  #define FTS5_TOKEN_COLOCATED    0x0001      /* Same position as prev. token */
  
  /*
  ** END OF CUSTOM TOKENIZERS
  *************************************************************************/
  
  /*************************************************************************
  ** FTS5 EXTENSION REGISTRATION API
  */
  typedef struct fts5_api fts5_api;
  struct fts5_api {
    int iVersion;                   /* Currently always set to 2 */
  
    /* Create a new tokenizer */
    int (*xCreateTokenizer)(
      fts5_api *pApi,
      const char *zName,
      void *pContext,
      fts5_tokenizer *pTokenizer,
      void (*xDestroy)(void*)
    );
  
    /* Find an existing tokenizer */
    int (*xFindTokenizer)(
      fts5_api *pApi,
      const char *zName,
      void **ppContext,
      fts5_tokenizer *pTokenizer
    );
  
    /* Create a new auxiliary function */
    int (*xCreateFunction)(
      fts5_api *pApi,
      const char *zName,
      void *pContext,
      fts5_extension_function xFunction,
      void (*xDestroy)(void*)
    );
  };
  
  /*
  ** END OF REGISTRATION API
  *************************************************************************/
  
  #ifdef __cplusplus
  }  /* end of the 'extern "C"' block */
  #endif
  
  #endif /* _FTS5_H */
  
  /******** End of fts5.h *********/
  