text: /*
  ** 2007 August 28
  **
  ** 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 file contains the common header for all mutex implementations.
  ** The sqliteInt.h header #includes this file so that it is available
  ** to all source files.  We break it out in an effort to keep the code
  ** better organized.
  **
  ** NOTE:  source files should *not* #include this header file directly.
  ** Source files should #include the sqliteInt.h file and let that file
  ** include this one indirectly.
  */
  
  
  /*
  ** Figure out what version of the code to use.  The choices are
  **
  **   SQLITE_MUTEX_OMIT         No mutex logic.  Not even stubs.  The
  **                             mutexes implementation cannot be overridden
  **                             at start-time.
  **
  **   SQLITE_MUTEX_NOOP         For single-threaded applications.  No
  **                             mutual exclusion is provided.  But this
  **                             implementation can be overridden at
  **                             start-time.
  **
  **   SQLITE_MUTEX_PTHREADS     For multi-threaded applications on Unix.
  **
  **   SQLITE_MUTEX_W32          For multi-threaded applications on Win32.
  **
  **   SQLITE_MUTEX_OS2          For multi-threaded applications on OS/2.
  */
  #if !SQLITE_THREADSAFE
  # define SQLITE_MUTEX_OMIT
  #endif
  #if SQLITE_THREADSAFE && !defined(SQLITE_MUTEX_NOOP)
  #  if SQLITE_OS_UNIX
  #    define SQLITE_MUTEX_PTHREADS
  #  elif SQLITE_OS_WIN
  #    define SQLITE_MUTEX_W32
  #  elif SQLITE_OS_OS2
  #    define SQLITE_MUTEX_OS2
  #  else
  #    define SQLITE_MUTEX_NOOP
  #  endif
  #endif
  
  #ifdef SQLITE_MUTEX_OMIT
  /*
  ** If this is a no-op implementation, implement everything as macros.
  */
  #define sqlite3_mutex_alloc(X)    ((sqlite3_mutex*)8)
  #define sqlite3_mutex_free(X)
  #define sqlite3_mutex_enter(X)    
  #define sqlite3_mutex_try(X)      SQLITE_OK
  #define sqlite3_mutex_leave(X)    
  #define sqlite3_mutex_held(X)     ((void)(X),1)
  #define sqlite3_mutex_notheld(X)  ((void)(X),1)
  #define sqlite3MutexAlloc(X)      ((sqlite3_mutex*)8)
  #define sqlite3MutexInit()        SQLITE_OK
  #define sqlite3MutexEnd()
  #define MUTEX_LOGIC(X)
  #else
  #define MUTEX_LOGIC(X)            X
  #endif /* defined(SQLITE_MUTEX_OMIT) */
  