text: /***********************************************************
  Copyright (C) 1994 Steen Lumholt.
  
                          All Rights Reserved
  
  ******************************************************************/
  
  /* _tkinter.c -- Interface to libtk.a and libtcl.a. */
  
  /* TCL/TK VERSION INFO:
  
      Only Tcl/Tk 8.4 and later are supported.  Older versions are not
      supported. Use Python 3.4 or older if you cannot upgrade your
      Tcl/Tk libraries.
  */
  
  /* XXX Further speed-up ideas, involving Tcl 8.0 features:
  
     - Register a new Tcl type, "Python callable", which can be called more
     efficiently and passed to Tcl_EvalObj() directly (if this is possible).
  
  */
  
  #define PY_SSIZE_T_CLEAN
  
  #include "Python.h"
  #include <ctype.h>
  
  #ifdef MS_WINDOWS
  #include <windows.h>
  #endif
  
  #define CHECK_SIZE(size, elemsize) \
      ((size_t)(size) <= Py_MIN((size_t)INT_MAX, UINT_MAX / (size_t)(elemsize)))
  
  /* If Tcl is compiled for threads, we must also define TCL_THREAD. We define
     it always; if Tcl is not threaded, the thread functions in
     Tcl are empty.  */
  #define TCL_THREADS
  
  #ifdef TK_FRAMEWORK
  #include <Tcl/tcl.h>
  #include <Tk/tk.h>
  #else
  #include <tcl.h>
  #include <tk.h>
  #endif
  
  #include "tkinter.h"
  
  #if TK_HEX_VERSION < 0x08040200
  #error "Tk older than 8.4 not supported"
  #endif
  
  #if TK_HEX_VERSION >= 0x08050208 && TK_HEX_VERSION < 0x08060000 || \
      TK_HEX_VERSION >= 0x08060200
  #define HAVE_LIBTOMMATH
  #include <tclTomMath.h>
  #endif
  
  #if !(defined(MS_WINDOWS) || defined(__CYGWIN__))
  #define HAVE_CREATEFILEHANDLER
  #endif
  
  #ifdef HAVE_CREATEFILEHANDLER
  
  /* This bit is to ensure that TCL_UNIX_FD is defined and doesn't interfere
     with the proper calculation of FHANDLETYPE == TCL_UNIX_FD below. */
  #ifndef TCL_UNIX_FD
  #  ifdef TCL_WIN_SOCKET
  #    define TCL_UNIX_FD (! TCL_WIN_SOCKET)
  #  else
  #    define TCL_UNIX_FD 1
  #  endif
  #endif
  
  /* Tcl_CreateFileHandler() changed several times; these macros deal with the
     messiness.  In Tcl 8.0 and later, it is not available on Windows (and on
     Unix, only because Jack added it back); when available on Windows, it only
     applies to sockets. */
  
  #ifdef MS_WINDOWS
  #define FHANDLETYPE TCL_WIN_SOCKET
  #else
  #define FHANDLETYPE TCL_UNIX_FD
  #endif
  
  /* If Tcl can wait for a Unix file descriptor, define the EventHook() routine
     which uses this to handle Tcl events while the user is typing commands. */
  
  #if FHANDLETYPE == TCL_UNIX_FD
  #define WAIT_FOR_STDIN
  #endif
  
  #endif /* HAVE_CREATEFILEHANDLER */
  
  /* Use OS native encoding for converting between Python strings and
     Tcl objects.
     On Windows use UTF-16 (or UTF-32 for 32-bit Tcl_UniChar) with the
     "surrogatepass" error handler for converting to/from Tcl Unicode objects.
     On Linux use UTF-8 with the "surrogateescape" error handler for converting
     to/from Tcl String objects. */
  #ifdef MS_WINDOWS
  #define USE_TCL_UNICODE 1
  #else
  #define USE_TCL_UNICODE 0
  #endif
  
  #if PY_LITTLE_ENDIAN
  #define NATIVE_BYTEORDER -1
  #else
  #define NATIVE_BYTEORDER 1
  #endif
  
  #ifdef MS_WINDOWS
  #include <conio.h>
  #define WAIT_FOR_STDIN
  
  static PyObject *
  _get_tcl_lib_path()
  {
      static PyObject *tcl_library_path = NULL;
      static int already_checked = 0;
  
      if (already_checked == 0) {
          PyObject *prefix;
          struct stat stat_buf;
          int stat_return_value;
  
          prefix = PyUnicode_FromWideChar(Py_GetPrefix(), -1);
          if (prefix == NULL) {
              return NULL;
          }
  
          /* Check expected location for an installed Python first */
          tcl_library_path = PyUnicode_FromString("\\tcl\\tcl" TCL_VERSION);
          if (tcl_library_path == NULL) {
              return NULL;
          }
          tcl_library_path = PyUnicode_Concat(prefix, tcl_library_path);
          if (tcl_library_path == NULL) {
              return NULL;
          }
          stat_return_value = _Py_stat(tcl_library_path, &stat_buf);
          if (stat_return_value == -2) {
              return NULL;
          }
          if (stat_return_value == -1) {
              /* install location doesn't exist, reset errno and see if
                 we're a repository build */
              errno = 0;
  #ifdef Py_TCLTK_DIR
              tcl_library_path = PyUnicode_FromString(
                                      Py_TCLTK_DIR "\\lib\\tcl" TCL_VERSION);
              if (tcl_library_path == NULL) {
                  return NULL;
              }
              stat_return_value = _Py_stat(tcl_library_path, &stat_buf);
              if (stat_return_value == -2) {
                  return NULL;
              }
              if (stat_return_value == -1) {
                  /* tcltkDir for a repository build doesn't exist either,
                     reset errno and leave Tcl to its own devices */
                  errno = 0;
                  tcl_library_path = NULL;
              }
  #else
              tcl_library_path = NULL;
  #endif
          }
          already_checked = 1;
      }
      return tcl_library_path;
  }
  #endif /* MS_WINDOWS */
  
  /* The threading situation is complicated.  Tcl is not thread-safe, except
     when configured with --enable-threads.
  
     So we need to use a lock around all uses of Tcl.  Previously, the
     Python interpreter lock was used for this.  However, this causes
     problems when other Python threads need to run while Tcl is blocked
     waiting for events.
  
     To solve this problem, a separate lock for Tcl is introduced.
     Holding it is incompatible with holding Python's interpreter lock.
     The following four macros manipulate both locks together.
  
     ENTER_TCL and LEAVE_TCL are brackets, just like
     Py_BEGIN_ALLOW_THREADS and Py_END_ALLOW_THREADS.  They should be
     used whenever a call into Tcl is made that could call an event
     handler, or otherwise affect the state of a Tcl interpreter.  These
     assume that the surrounding code has the Python interpreter lock;
     inside the brackets, the Python interpreter lock has been released
     and the lock for Tcl has been acquired.
  
     Sometimes, it is necessary to have both the Python lock and the Tcl
     lock.  (For example, when transferring data from the Tcl
     interpreter result to a Python string object.)  This can be done by
     using different macros to close the ENTER_TCL block: ENTER_OVERLAP
     reacquires the Python lock (and restores the thread state) but
     doesn't release the Tcl lock; LEAVE_OVERLAP_TCL releases the Tcl
     lock.
  
     By contrast, ENTER_PYTHON and LEAVE_PYTHON are used in Tcl event
     handlers when the handler needs to use Python.  Such event handlers
     are entered while the lock for Tcl is held; the event handler
     presumably needs to use Python.  ENTER_PYTHON releases the lock for
     Tcl and acquires the Python interpreter lock, restoring the
     appropriate thread state, and LEAVE_PYTHON releases the Python
     interpreter lock and re-acquires the lock for Tcl.  It is okay for
     ENTER_TCL/LEAVE_TCL pairs to be contained inside the code between
     ENTER_PYTHON and LEAVE_PYTHON.
  
     These locks expand to several statements and brackets; they should
     not be used in branches of if statements and the like.
  
     If Tcl is threaded, this approach won't work anymore. The Tcl
     interpreter is only valid in the thread that created it, and all Tk
     activity must happen in this thread, also. That means that the
     mainloop must be invoked in the thread that created the
     interpreter. Invoking commands from other threads is possible;
     _tkinter will queue an event for the interpreter thread, which will
     then execute the command and pass back the result. If the main
     thread is not in the mainloop, and invoking commands causes an
     exception; if the main loop is running but not processing events,
     the command invocation will block.
  
     In addition, for a threaded Tcl, a single global tcl_tstate won't
     be sufficient anymore, since multiple Tcl interpreters may
     simultaneously dispatch in different threads. So we use the Tcl TLS
     API.
  
  */
  
  static PyThread_type_lock tcl_lock = 0;
  
  #ifdef TCL_THREADS
  static Tcl_ThreadDataKey state_key;
  typedef PyThreadState *ThreadSpecificData;
  #define tcl_tstate \
      (*(PyThreadState**)Tcl_GetThreadData(&state_key, sizeof(PyThreadState*)))
  #else
  static PyThreadState *tcl_tstate = NULL;
  #endif
  
  #define ENTER_TCL \
      { PyThreadState *tstate = PyThreadState_Get(); \
        Py_BEGIN_ALLOW_THREADS \
        if(tcl_lock)PyThread_acquire_lock(tcl_lock, 1); \
        tcl_tstate = tstate;
  
  #define LEAVE_TCL \
      tcl_tstate = NULL; \
      if(tcl_lock)PyThread_release_lock(tcl_lock); \
      Py_END_ALLOW_THREADS}
  
  #define ENTER_OVERLAP \
      Py_END_ALLOW_THREADS
  
  #define LEAVE_OVERLAP_TCL \
      tcl_tstate = NULL; if(tcl_lock)PyThread_release_lock(tcl_lock); }
  
  #define ENTER_PYTHON \
      { PyThreadState *tstate = tcl_tstate; tcl_tstate = NULL; \
        if(tcl_lock) \
          PyThread_release_lock(tcl_lock); \
        PyEval_RestoreThread((tstate)); }
  
  #define LEAVE_PYTHON \
      { PyThreadState *tstate = PyEval_SaveThread(); \
        if(tcl_lock)PyThread_acquire_lock(tcl_lock, 1); \
        tcl_tstate = tstate; }
  
  #define CHECK_TCL_APPARTMENT \
      if (((TkappObject *)self)->threaded && \
          ((TkappObject *)self)->thread_id != Tcl_GetCurrentThread()) { \
          PyErr_SetString(PyExc_RuntimeError, \
                          "Calling Tcl from different apartment"); \
          return 0; \
      }
  
  #ifndef FREECAST
  #define FREECAST (char *)
  #endif
  
  /**** Tkapp Object Declaration ****/
  
  static PyObject *Tkapp_Type;
  
  typedef struct {
      PyObject_HEAD
      Tcl_Interp *interp;
      int wantobjects;
      int threaded; /* True if tcl_platform[threaded] */
      Tcl_ThreadId thread_id;
      int dispatching;
      /* We cannot include tclInt.h, as this is internal.
         So we cache interesting types here. */
      const Tcl_ObjType *OldBooleanType;
      const Tcl_ObjType *BooleanType;
      const Tcl_ObjType *ByteArrayType;
      const Tcl_ObjType *DoubleType;
      const Tcl_ObjType *IntType;
      const Tcl_ObjType *WideIntType;
      const Tcl_ObjType *BignumType;
      const Tcl_ObjType *ListType;
      const Tcl_ObjType *ProcBodyType;
      const Tcl_ObjType *StringType;
  } TkappObject;
  
  #define Tkapp_Interp(v) (((TkappObject *) (v))->interp)
  
  #define DEBUG_REFCNT(v) (printf("DEBUG: id=%p, refcnt=%i\n", \
  (void *) v, Py_REFCNT(v)))
  
  
  
  /**** Error Handling ****/
  
  static PyObject *Tkinter_TclError;
  static int quitMainLoop = 0;
  static int errorInCmd = 0;
  static PyObject *excInCmd;
  static PyObject *valInCmd;
  static PyObject *trbInCmd;
  
  #ifdef TKINTER_PROTECT_LOADTK
  static int tk_load_failed = 0;
  #endif
  
  
  static PyObject *Tkapp_UnicodeResult(TkappObject *);
  
  static PyObject *
  Tkinter_Error(TkappObject *self)
  {
      PyObject *res = Tkapp_UnicodeResult(self);
      if (res != NULL) {
          PyErr_SetObject(Tkinter_TclError, res);
          Py_DECREF(res);
      }
      return NULL;
  }
  
  
  
  /**** Utils ****/
  
  static int Tkinter_busywaitinterval = 20;
  
  #ifndef MS_WINDOWS
  
  /* Millisecond sleep() for Unix platforms. */
  
  static void
  Sleep(int milli)
  {
      /* XXX Too bad if you don't have select(). */
      struct timeval t;
      t.tv_sec = milli/1000;
      t.tv_usec = (milli%1000) * 1000;
      select(0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &t);
  }
  #endif /* MS_WINDOWS */
  
  /* Wait up to 1s for the mainloop to come up. */
  
  static int
  WaitForMainloop(TkappObject* self)
  {
      int i;
      for (i = 0; i < 10; i++) {
          if (self->dispatching)
              return 1;
          Py_BEGIN_ALLOW_THREADS
          Sleep(100);
          Py_END_ALLOW_THREADS
      }
      if (self->dispatching)
          return 1;
      PyErr_SetString(PyExc_RuntimeError, "main thread is not in main loop");
      return 0;
  }
  
  
  
  #define ARGSZ 64
  
  
  
  static PyObject *
  unicodeFromTclStringAndSize(const char *s, Py_ssize_t size)
  {
      PyObject *r = PyUnicode_DecodeUTF8(s, size, NULL);
      if (r != NULL || !PyErr_ExceptionMatches(PyExc_UnicodeDecodeError)) {
          return r;
      }
  
      char *buf = NULL;
      PyErr_Clear();
      /* Tcl encodes null character as \xc0\x80.
         https://en.wikipedia.org/wiki/UTF-8#Modified_UTF-8 */
      if (memchr(s, '\xc0', size)) {
          char *q;
          const char *e = s + size;
          q = buf = (char *)PyMem_Malloc(size);
          if (buf == NULL) {
              PyErr_NoMemory();
              return NULL;
          }
          while (s != e) {
              if (s + 1 != e && s[0] == '\xc0' && s[1] == '\x80') {
                  *q++ = '\0';
                  s += 2;
              }
              else
                  *q++ = *s++;
          }
          s = buf;
          size = q - s;
      }
      r = PyUnicode_DecodeUTF8(s, size, "surrogateescape");
      if (buf != NULL) {
          PyMem_Free(buf);
      }
      if (r == NULL || PyUnicode_KIND(r) == PyUnicode_1BYTE_KIND) {
          return r;
      }
  
      /* In CESU-8 non-BMP characters are represented as a surrogate pair,
         like in UTF-16, and then each surrogate code point is encoded in UTF-8.
         https://en.wikipedia.org/wiki/CESU-8 */
      Py_ssize_t len = PyUnicode_GET_LENGTH(r);
      Py_ssize_t i, j;
      /* All encoded surrogate characters start with \xED. */
      i = PyUnicode_FindChar(r, 0xdcED, 0, len, 1);
      if (i == -2) {
          Py_DECREF(r);
          return NULL;
      }
      if (i == -1) {
          return r;
      }
      Py_UCS4 *u = PyUnicode_AsUCS4Copy(r);
      Py_DECREF(r);
      if (u == NULL) {
          return NULL;
      }
      Py_UCS4 ch;
      for (j = i; i < len; i++, u[j++] = ch) {
          Py_UCS4 ch1, ch2, ch3, high, low;
          /* Low surrogates U+D800 - U+DBFF are encoded as
             \xED\xA0\x80 - \xED\xAF\xBF. */
          ch1 = ch = u[i];
          if (ch1 != 0xdcED) continue;
          ch2 = u[i + 1];
          if (!(0xdcA0 <= ch2 && ch2 <= 0xdcAF)) continue;
          ch3 = u[i + 2];
          if (!(0xdc80 <= ch3 && ch3 <= 0xdcBF)) continue;
          high = 0xD000 | ((ch2 & 0x3F) << 6) | (ch3 & 0x3F);
          assert(Py_UNICODE_IS_HIGH_SURROGATE(high));
          /* High surrogates U+DC00 - U+DFFF are encoded as
             \xED\xB0\x80 - \xED\xBF\xBF. */
          ch1 = u[i + 3];
          if (ch1 != 0xdcED) continue;
          ch2 = u[i + 4];
          if (!(0xdcB0 <= ch2 && ch2 <= 0xdcBF)) continue;
          ch3 = u[i + 5];
          if (!(0xdc80 <= ch3 && ch3 <= 0xdcBF)) continue;
          low = 0xD000 | ((ch2 & 0x3F) << 6) | (ch3 & 0x3F);
          assert(Py_UNICODE_IS_HIGH_SURROGATE(high));
          ch = Py_UNICODE_JOIN_SURROGATES(high, low);
          i += 5;
      }
      r = PyUnicode_FromKindAndData(PyUnicode_4BYTE_KIND, u, j);
      PyMem_Free(u);
      return r;
  }
  
  static PyObject *
  unicodeFromTclString(const char *s)
  {
      return unicodeFromTclStringAndSize(s, strlen(s));
  }
  
  static PyObject *
  unicodeFromTclObj(Tcl_Obj *value)
  {
      int len;
  #if USE_TCL_UNICODE
      int byteorder = NATIVE_BYTEORDER;
      const Tcl_UniChar *u = Tcl_GetUnicodeFromObj(value, &len);
      if (sizeof(Tcl_UniChar) == 2)
          return PyUnicode_DecodeUTF16((const char *)u, len * 2,
                                       "surrogatepass", &byteorder);
      else if (sizeof(Tcl_UniChar) == 4)
          return PyUnicode_DecodeUTF32((const char *)u, len * 4,
                                       "surrogatepass", &byteorder);
      else
          Py_UNREACHABLE();
  #else
      const char *s = Tcl_GetStringFromObj(value, &len);
      return unicodeFromTclStringAndSize(s, len);
  #endif
  }
  
  
  static PyObject *
  Split(const char *list)
  {
      int argc;
      const char **argv;
      PyObject *v;
  
      if (list == NULL) {
          Py_RETURN_NONE;
      }
  
      if (Tcl_SplitList((Tcl_Interp *)NULL, list, &argc, &argv) != TCL_OK) {
          /* Not a list.
           * Could be a quoted string containing funnies, e.g. {"}.
           * Return the string itself.
           */
          return unicodeFromTclString(list);
      }
  
      if (argc == 0)
          v = PyUnicode_FromString("");
      else if (argc == 1)
          v = unicodeFromTclString(argv[0]);
      else if ((v = PyTuple_New(argc)) != NULL) {
          int i;
          PyObject *w;
  
          for (i = 0; i < argc; i++) {
              if ((w = Split(argv[i])) == NULL) {
                  Py_DECREF(v);
                  v = NULL;
                  break;
              }
              PyTuple_SET_ITEM(v, i, w);
          }
      }
      Tcl_Free(FREECAST argv);
      return v;
  }
  
  /* In some cases, Tcl will still return strings that are supposed to
     be lists. SplitObj walks through a nested tuple, finding string
     objects that need to be split. */
  
  static PyObject *
  SplitObj(PyObject *arg)
  {
      if (PyTuple_Check(arg)) {
          Py_ssize_t i, size;
          PyObject *elem, *newelem, *result;
  
          size = PyTuple_GET_SIZE(arg);
          result = NULL;
          /* Recursively invoke SplitObj for all tuple items.
             If this does not return a new object, no action is
             needed. */
          for(i = 0; i < size; i++) {
              elem = PyTuple_GET_ITEM(arg, i);
              newelem = SplitObj(elem);
              if (!newelem) {
                  Py_XDECREF(result);
                  return NULL;
              }
              if (!result) {
                  Py_ssize_t k;
                  if (newelem == elem) {
                      Py_DECREF(newelem);
                      continue;
                  }
                  result = PyTuple_New(size);
                  if (!result)
                      return NULL;
                  for(k = 0; k < i; k++) {
                      elem = PyTuple_GET_ITEM(arg, k);
                      Py_INCREF(elem);
                      PyTuple_SET_ITEM(result, k, elem);
                  }
              }
              PyTuple_SET_ITEM(result, i, newelem);
          }
          if (result)
              return result;
          /* Fall through, returning arg. */
      }
      else if (PyList_Check(arg)) {
          Py_ssize_t i, size;
          PyObject *elem, *newelem, *result;
  
          size = PyList_GET_SIZE(arg);
          result = PyTuple_New(size);
          if (!result)
              return NULL;
          /* Recursively invoke SplitObj for all list items. */
          for(i = 0; i < size; i++) {
              elem = PyList_GET_ITEM(arg, i);
              newelem = SplitObj(elem);
              if (!newelem) {
                  Py_XDECREF(result);
                  return NULL;
              }
              PyTuple_SET_ITEM(result, i, newelem);
          }
          return result;
      }
      else if (PyUnicode_Check(arg)) {
          int argc;
          const char **argv;
          const char *list = PyUnicode_AsUTF8(arg);
  
          if (list == NULL ||
              Tcl_SplitList((Tcl_Interp *)NULL, list, &argc, &argv) != TCL_OK) {
              Py_INCREF(arg);
              return arg;
          }
          Tcl_Free(FREECAST argv);
          if (argc > 1)
              return Split(list);
          /* Fall through, returning arg. */
      }
      else if (PyBytes_Check(arg)) {
          int argc;
          const char **argv;
          const char *list = PyBytes_AS_STRING(arg);
  
          if (Tcl_SplitList((Tcl_Interp *)NULL, (char *)list, &argc, &argv) != TCL_OK) {
              Py_INCREF(arg);
              return arg;
          }
          Tcl_Free(FREECAST argv);
          if (argc > 1)
              return Split(PyBytes_AS_STRING(arg));
          /* Fall through, returning arg. */
      }
      Py_INCREF(arg);
      return arg;
  }
  
  
  /*[clinic input]
  module _tkinter
  class _tkinter.tkapp "TkappObject *" "&Tkapp_Type_spec"
  class _tkinter.Tcl_Obj "PyTclObject *" "&PyTclObject_Type_spec"
  class _tkinter.tktimertoken "TkttObject *" "&Tktt_Type_spec"
  [clinic start generated code]*/
  /*[clinic end generated code: output=da39a3ee5e6b4b0d input=b1ebf15c162ee229]*/
  
  /**** Tkapp Object ****/
  
  #ifndef WITH_APPINIT
  int
  Tcl_AppInit(Tcl_Interp *interp)
  {
      const char * _tkinter_skip_tk_init;
  
      if (Tcl_Init(interp) == TCL_ERROR) {
          PySys_WriteStderr("Tcl_Init error: %s\n", Tcl_GetStringResult(interp));
          return TCL_ERROR;
      }
  
      _tkinter_skip_tk_init = Tcl_GetVar(interp,
                      "_tkinter_skip_tk_init", TCL_GLOBAL_ONLY);
      if (_tkinter_skip_tk_init != NULL &&
                      strcmp(_tkinter_skip_tk_init, "1") == 0) {
          return TCL_OK;
      }
  
  #ifdef TKINTER_PROTECT_LOADTK
      if (tk_load_failed) {
          PySys_WriteStderr("Tk_Init error: %s\n", TKINTER_LOADTK_ERRMSG);
          return TCL_ERROR;
      }
  #endif
  
      if (Tk_Init(interp) == TCL_ERROR) {
  #ifdef TKINTER_PROTECT_LOADTK
          tk_load_failed = 1;
  #endif
          PySys_WriteStderr("Tk_Init error: %s\n", Tcl_GetStringResult(interp));
          return TCL_ERROR;
      }
  
      return TCL_OK;
  }
  #endif /* !WITH_APPINIT */
  
  
  
  
  /* Initialize the Tk application; see the `main' function in
   * `tkMain.c'.
   */
  
  static void EnableEventHook(void); /* Forward */
  static void DisableEventHook(void); /* Forward */
  
  static TkappObject *
  Tkapp_New(const char *screenName, const char *className,
            int interactive, int wantobjects, int wantTk, int sync,
            const char *use)
  {
      TkappObject *v;
      char *argv0;
  
      v = PyObject_New(TkappObject, (PyTypeObject *) Tkapp_Type);
      if (v == NULL)
          return NULL;
  
      v->interp = Tcl_CreateInterp();
      v->wantobjects = wantobjects;
      v->threaded = Tcl_GetVar2Ex(v->interp, "tcl_platform", "threaded",
                                  TCL_GLOBAL_ONLY) != NULL;
      v->thread_id = Tcl_GetCurrentThread();
      v->dispatching = 0;
  
  #ifndef TCL_THREADS
      if (v->threaded) {
          PyErr_SetString(PyExc_RuntimeError,
                          "Tcl is threaded but _tkinter is not");
          Py_DECREF(v);
          return 0;
      }
  #endif
      if (v->threaded && tcl_lock) {
          /* If Tcl is threaded, we don't need the lock. */
          PyThread_free_lock(tcl_lock);
          tcl_lock = NULL;
      }
  
      v->OldBooleanType = Tcl_GetObjType("boolean");
      v->BooleanType = Tcl_GetObjType("booleanString");
      v->ByteArrayType = Tcl_GetObjType("bytearray");
      v->DoubleType = Tcl_GetObjType("double");
      v->IntType = Tcl_GetObjType("int");
      v->WideIntType = Tcl_GetObjType("wideInt");
      v->BignumType = Tcl_GetObjType("bignum");
      v->ListType = Tcl_GetObjType("list");
      v->ProcBodyType = Tcl_GetObjType("procbody");
      v->StringType = Tcl_GetObjType("string");
  
      /* Delete the 'exit' command, which can screw things up */
      Tcl_DeleteCommand(v->interp, "exit");
  
      if (screenName != NULL)
          Tcl_SetVar2(v->interp, "env", "DISPLAY",
                      screenName, TCL_GLOBAL_ONLY);
  
      if (interactive)
          Tcl_SetVar(v->interp, "tcl_interactive", "1", TCL_GLOBAL_ONLY);
      else
          Tcl_SetVar(v->interp, "tcl_interactive", "0", TCL_GLOBAL_ONLY);
  
      /* This is used to get the application class for Tk 4.1 and up */
      argv0 = (char*)PyMem_Malloc(strlen(className) + 1);
      if (!argv0) {
          PyErr_NoMemory();
          Py_DECREF(v);
          return NULL;
      }
  
      strcpy(argv0, className);
      if (Py_ISUPPER(argv0[0]))
          argv0[0] = Py_TOLOWER(argv0[0]);
      Tcl_SetVar(v->interp, "argv0", argv0, TCL_GLOBAL_ONLY);
      PyMem_Free(argv0);
  
      if (! wantTk) {
          Tcl_SetVar(v->interp,
                          "_tkinter_skip_tk_init", "1", TCL_GLOBAL_ONLY);
      }
  #ifdef TKINTER_PROTECT_LOADTK
      else if (tk_load_failed) {
          Tcl_SetVar(v->interp,
                          "_tkinter_tk_failed", "1", TCL_GLOBAL_ONLY);
      }
  #endif
  
      /* some initial arguments need to be in argv */
      if (sync || use) {
          char *args;
          Py_ssize_t len = 0;
  
          if (sync)
              len += sizeof "-sync";
          if (use)
              len += strlen(use) + sizeof "-use ";  /* never overflows */
  
          args = (char*)PyMem_Malloc(len);
          if (!args) {
              PyErr_NoMemory();
              Py_DECREF(v);
              return NULL;
          }
  
          args[0] = '\0';
          if (sync)
              strcat(args, "-sync");
          if (use) {
              if (sync)
                  strcat(args, " ");
              strcat(args, "-use ");
              strcat(args, use);
          }
  
          Tcl_SetVar(v->interp, "argv", args, TCL_GLOBAL_ONLY);
          PyMem_Free(args);
      }
  
  #ifdef MS_WINDOWS
      {
          PyObject *str_path;
          PyObject *utf8_path;
          DWORD ret;
  
          ret = GetEnvironmentVariableW(L"TCL_LIBRARY", NULL, 0);
          if (!ret && GetLastError() == ERROR_ENVVAR_NOT_FOUND) {
              str_path = _get_tcl_lib_path();
              if (str_path == NULL && PyErr_Occurred()) {
                  return NULL;
              }
              if (str_path != NULL) {
                  utf8_path = PyUnicode_AsUTF8String(str_path);
                  if (utf8_path == NULL) {
                      return NULL;
                  }
                  Tcl_SetVar(v->interp,
                             "tcl_library",
                             PyBytes_AS_STRING(utf8_path),
                             TCL_GLOBAL_ONLY);
                  Py_DECREF(utf8_path);
              }
          }
      }
  #endif
  
      if (Tcl_AppInit(v->interp) != TCL_OK) {
          PyObject *result = Tkinter_Error(v);
  #ifdef TKINTER_PROTECT_LOADTK
          if (wantTk) {
              const char *_tkinter_tk_failed;
              _tkinter_tk_failed = Tcl_GetVar(v->interp,
                              "_tkinter_tk_failed", TCL_GLOBAL_ONLY);
  
              if ( _tkinter_tk_failed != NULL &&
                              strcmp(_tkinter_tk_failed, "1") == 0) {
                  tk_load_failed = 1;
              }
          }
  #endif
          Py_DECREF((PyObject *)v);
          return (TkappObject *)result;
      }
  
      EnableEventHook();
  
      return v;
  }
  
  
  static void
  Tkapp_ThreadSend(TkappObject *self, Tcl_Event *ev,
                   Tcl_Condition *cond, Tcl_Mutex *mutex)
  {
      Py_BEGIN_ALLOW_THREADS;
      Tcl_MutexLock(mutex);
      Tcl_ThreadQueueEvent(self->thread_id, ev, TCL_QUEUE_TAIL);
      Tcl_ThreadAlert(self->thread_id);
      Tcl_ConditionWait(cond, mutex, NULL);
      Tcl_MutexUnlock(mutex);
      Py_END_ALLOW_THREADS
  }
  
  
  /** Tcl Eval **/
  
  typedef struct {
      PyObject_HEAD
      Tcl_Obj *value;
      PyObject *string; /* This cannot cause cycles. */
  } PyTclObject;
  
  static PyObject *PyTclObject_Type;
  #define PyTclObject_Check(v) Py_IS_TYPE(v, (PyTypeObject *) PyTclObject_Type)
  
  static PyObject *
  newPyTclObject(Tcl_Obj *arg)
  {
      PyTclObject *self;
      self = PyObject_New(PyTclObject, (PyTypeObject *) PyTclObject_Type);
      if (self == NULL)
          return NULL;
      Tcl_IncrRefCount(arg);
      self->value = arg;
      self->string = NULL;
      return (PyObject*)self;
  }
  
  static void
  PyTclObject_dealloc(PyTclObject *self)
  {
      PyObject *tp = (PyObject *) Py_TYPE(self);
      Tcl_DecrRefCount(self->value);
      Py_XDECREF(self->string);
      PyObject_Del(self);
      Py_DECREF(tp);
  }
  
  /* Like _str, but create Unicode if necessary. */
  PyDoc_STRVAR(PyTclObject_string__doc__,
  "the string representation of this object, either as str or bytes");
  
  static PyObject *
  PyTclObject_string(PyTclObject *self, void *ignored)
  {
      if (!self->string) {
          self->string = unicodeFromTclObj(self->value);
          if (!self->string)
              return NULL;
      }
      Py_INCREF(self->string);
      return self->string;
  }
  
  static PyObject *
  PyTclObject_str(PyTclObject *self)
  {
      if (self->string) {
          Py_INCREF(self->string);
          return self->string;
      }
      /* XXX Could chache result if it is non-ASCII. */
      return unicodeFromTclObj(self->value);
  }
  
  static PyObject *
  PyTclObject_repr(PyTclObject *self)
  {
      PyObject *repr, *str = PyTclObject_str(self);
      if (str == NULL)
          return NULL;
      repr = PyUnicode_FromFormat("<%s object: %R>",
                                  self->value->typePtr->name, str);
      Py_DECREF(str);
      return repr;
  }
  
  static PyObject *
  PyTclObject_richcompare(PyObject *self, PyObject *other, int op)
  {
      int result;
  
      /* neither argument should be NULL, unless something's gone wrong */
      if (self == NULL || other == NULL) {
          PyErr_BadInternalCall();
          return NULL;
      }
  
      /* both arguments should be instances of PyTclObject */
      if (!PyTclObject_Check(self) || !PyTclObject_Check(other)) {
          Py_RETURN_NOTIMPLEMENTED;
      }
  
      if (self == other)
          /* fast path when self and other are identical */
          result = 0;
      else
          result = strcmp(Tcl_GetString(((PyTclObject *)self)->value),
                          Tcl_GetString(((PyTclObject *)other)->value));
      Py_RETURN_RICHCOMPARE(result, 0, op);
  }
  
  PyDoc_STRVAR(get_typename__doc__, "name of the Tcl type");
  
  static PyObject*
  get_typename(PyTclObject* obj, void* ignored)
  {
      return unicodeFromTclString(obj->value->typePtr->name);
  }
  
  
  static PyGetSetDef PyTclObject_getsetlist[] = {
      {"typename", (getter)get_typename, NULL, get_typename__doc__},
      {"string", (getter)PyTclObject_string, NULL,
       PyTclObject_string__doc__},
      {0},
  };
  
  static PyType_Slot PyTclObject_Type_slots[] = {
      {Py_tp_dealloc, (destructor)PyTclObject_dealloc},
      {Py_tp_repr, (reprfunc)PyTclObject_repr},
      {Py_tp_str, (reprfunc)PyTclObject_str},
      {Py_tp_getattro, PyObject_GenericGetAttr},
      {Py_tp_richcompare, PyTclObject_richcompare},
      {Py_tp_getset, PyTclObject_getsetlist},
      {0, 0}
  };
  
  static PyType_Spec PyTclObject_Type_spec = {
      "_tkinter.Tcl_Obj",
      sizeof(PyTclObject),
      0,
      Py_TPFLAGS_DEFAULT,
      PyTclObject_Type_slots,
  };
  
  
  #if SIZE_MAX > INT_MAX
  #define CHECK_STRING_LENGTH(s) do {                                     \
          if (s != NULL && strlen(s) >= INT_MAX) {                        \
              PyErr_SetString(PyExc_OverflowError, "string is too long"); \
              return NULL;                                                \
          } } while(0)
  #else
  #define CHECK_STRING_LENGTH(s)
  #endif
  
  #ifdef HAVE_LIBTOMMATH
  static Tcl_Obj*
  asBignumObj(PyObject *value)
  {
      Tcl_Obj *result;
      int neg;
      PyObject *hexstr;
      const char *hexchars;
      mp_int bigValue;
  
      neg = Py_SIZE(value) < 0;
      hexstr = _PyLong_Format(value, 16);
      if (hexstr == NULL)
          return NULL;
      hexchars = PyUnicode_AsUTF8(hexstr);
      if (hexchars == NULL) {
          Py_DECREF(hexstr);
          return NULL;
      }
      hexchars += neg + 2; /* skip sign and "0x" */
      mp_init(&bigValue);
      if (mp_read_radix(&bigValue, hexchars, 16) != MP_OKAY) {
          mp_clear(&bigValue);
          Py_DECREF(hexstr);
          PyErr_NoMemory();
          return NULL;
      }
      Py_DECREF(hexstr);
      bigValue.sign = neg ? MP_NEG : MP_ZPOS;
      result = Tcl_NewBignumObj(&bigValue);
      mp_clear(&bigValue);
      if (result == NULL) {
          PyErr_NoMemory();
          return NULL;
      }
      return result;
  }
  #endif
  
  static Tcl_Obj*
  AsObj(PyObject *value)
  {
      Tcl_Obj *result;
  
      if (PyBytes_Check(value)) {
          if (PyBytes_GET_SIZE(value) >= INT_MAX) {
              PyErr_SetString(PyExc_OverflowError, "bytes object is too long");
              return NULL;
          }
          return Tcl_NewByteArrayObj((unsigned char *)PyBytes_AS_STRING(value),
                                     (int)PyBytes_GET_SIZE(value));
      }
  
      if (PyBool_Check(value))
          return Tcl_NewBooleanObj(PyObject_IsTrue(value));
  
      if (PyLong_CheckExact(value)) {
          int overflow;
          long longValue;
  #ifdef TCL_WIDE_INT_TYPE
          Tcl_WideInt wideValue;
  #endif
          longValue = PyLong_AsLongAndOverflow(value, &overflow);
          if (!overflow) {
              return Tcl_NewLongObj(longValue);
          }
          /* If there is an overflow in the long conversion,
             fall through to wideInt handling. */
  #ifdef TCL_WIDE_INT_TYPE
          if (_PyLong_AsByteArray((PyLongObject *)value,
                                  (unsigned char *)(void *)&wideValue,
                                  sizeof(wideValue),
                                  PY_LITTLE_ENDIAN,
                                  /* signed */ 1) == 0) {
              return Tcl_NewWideIntObj(wideValue);
          }
          PyErr_Clear();
  #endif
          /* If there is an overflow in the wideInt conversion,
             fall through to bignum handling. */
  #ifdef HAVE_LIBTOMMATH
          return asBignumObj(value);
  #endif
          /* If there is no wideInt or bignum support,
             fall through to default object handling. */
      }
  
      if (PyFloat_Check(value))
          return Tcl_NewDoubleObj(PyFloat_AS_DOUBLE(value));
  
      if (PyTuple_Check(value) || PyList_Check(value)) {
          Tcl_Obj **argv;
          Py_ssize_t size, i;
  
          size = PySequence_Fast_GET_SIZE(value);
          if (size == 0)
              return Tcl_NewListObj(0, NULL);
          if (!CHECK_SIZE(size, sizeof(Tcl_Obj *))) {
              PyErr_SetString(PyExc_OverflowError,
                              PyTuple_Check(value) ? "tuple is too long" :
                                                     "list is too long");
              return NULL;
          }
          argv = (Tcl_Obj **) PyMem_Malloc(((size_t)size) * sizeof(Tcl_Obj *));
          if (!argv) {
            PyErr_NoMemory();
            return NULL;
          }
          for (i = 0; i < size; i++)
            argv[i] = AsObj(PySequence_Fast_GET_ITEM(value,i));
          result = Tcl_NewListObj((int)size, argv);
          PyMem_Free(argv);
          return result;
      }
  
      if (PyUnicode_Check(value)) {
          if (PyUnicode_READY(value) == -1)
              return NULL;
  
          Py_ssize_t size = PyUnicode_GET_LENGTH(value);
          if (size == 0) {
              return Tcl_NewStringObj("", 0);
          }
          if (!CHECK_SIZE(size, sizeof(Tcl_UniChar))) {
              PyErr_SetString(PyExc_OverflowError, "string is too long");
              return NULL;
          }
          if (PyUnicode_IS_ASCII(value)) {
              return Tcl_NewStringObj((const char *)PyUnicode_DATA(value),
                                      (int)size);
          }
  
          PyObject *encoded;
  #if USE_TCL_UNICODE
          if (sizeof(Tcl_UniChar) == 2)
              encoded = _PyUnicode_EncodeUTF16(value,
                      "surrogatepass", NATIVE_BYTEORDER);
          else if (sizeof(Tcl_UniChar) == 4)
              encoded = _PyUnicode_EncodeUTF32(value,
                      "surrogatepass", NATIVE_BYTEORDER);
          else
              Py_UNREACHABLE();
  #else
          encoded = _PyUnicode_AsUTF8String(value, "surrogateescape");
  #endif
          if (!encoded) {
              return NULL;
          }
          size = PyBytes_GET_SIZE(encoded);
          if (size > INT_MAX) {
              Py_DECREF(encoded);
              PyErr_SetString(PyExc_OverflowError, "string is too long");
              return NULL;
          }
  #if USE_TCL_UNICODE
          result = Tcl_NewUnicodeObj((const Tcl_UniChar *)PyBytes_AS_STRING(encoded),
                                     (int)(size / sizeof(Tcl_UniChar)));
  #else
          result = Tcl_NewStringObj(PyBytes_AS_STRING(encoded), (int)size);
  #endif
          Py_DECREF(encoded);
          return result;
      }
  
      if (PyTclObject_Check(value)) {
          return ((PyTclObject*)value)->value;
      }
  
      {
          PyObject *v = PyObject_Str(value);
          if (!v)
              return 0;
          result = AsObj(v);
          Py_DECREF(v);
          return result;
      }
  }
  
  static PyObject *
  fromBoolean(TkappObject *tkapp, Tcl_Obj *value)
  {
      int boolValue;
      if (Tcl_GetBooleanFromObj(Tkapp_Interp(tkapp), value, &boolValue) == TCL_ERROR)
          return Tkinter_Error(tkapp);
      return PyBool_FromLong(boolValue);
  }
  
  static PyObject*
  fromWideIntObj(TkappObject *tkapp, Tcl_Obj *value)
  {
          Tcl_WideInt wideValue;
          if (Tcl_GetWideIntFromObj(Tkapp_Interp(tkapp), value, &wideValue) == TCL_OK) {
              if (sizeof(wideValue) <= SIZEOF_LONG_LONG)
                  return PyLong_FromLongLong(wideValue);
              return _PyLong_FromByteArray((unsigned char *)(void *)&wideValue,
                                           sizeof(wideValue),
                                           PY_LITTLE_ENDIAN,
                                           /* signed */ 1);
          }
          return NULL;
  }
  
  #ifdef HAVE_LIBTOMMATH
  static PyObject*
  fromBignumObj(TkappObject *tkapp, Tcl_Obj *value)
  {
      mp_int bigValue;
      unsigned long numBytes;
      unsigned char *bytes;
      PyObject *res;
  
      if (Tcl_GetBignumFromObj(Tkapp_Interp(tkapp), value, &bigValue) != TCL_OK)
          return Tkinter_Error(tkapp);
      numBytes = mp_unsigned_bin_size(&bigValue);
      bytes = PyMem_Malloc(numBytes);
      if (bytes == NULL) {
          mp_clear(&bigValue);
          return PyErr_NoMemory();
      }
      if (mp_to_unsigned_bin_n(&bigValue, bytes,
                                  &numBytes) != MP_OKAY) {
          mp_clear(&bigValue);
          PyMem_Free(bytes);
          return PyErr_NoMemory();
      }
      res = _PyLong_FromByteArray(bytes, numBytes,
                                  /* big-endian */ 0,
                                  /* unsigned */ 0);
      PyMem_Free(bytes);
      if (res != NULL && bigValue.sign == MP_NEG) {
          PyObject *res2 = PyNumber_Negative(res);
          Py_DECREF(res);
          res = res2;
      }
      mp_clear(&bigValue);
      return res;
  }
  #endif
  
  static PyObject*
  FromObj(TkappObject *tkapp, Tcl_Obj *value)
  {
      PyObject *result = NULL;
      Tcl_Interp *interp = Tkapp_Interp(tkapp);
  
      if (value->typePtr == NULL) {
          return unicodeFromTclObj(value);
      }
  
      if (value->typePtr == tkapp->BooleanType ||
          value->typePtr == tkapp->OldBooleanType) {
          return fromBoolean(tkapp, value);
      }
  
      if (value->typePtr == tkapp->ByteArrayType) {
          int size;
          char *data = (char*)Tcl_GetByteArrayFromObj(value, &size);
          return PyBytes_FromStringAndSize(data, size);
      }
  
      if (value->typePtr == tkapp->DoubleType) {
          return PyFloat_FromDouble(value->internalRep.doubleValue);
      }
  
      if (value->typePtr == tkapp->IntType) {
          long longValue;
          if (Tcl_GetLongFromObj(interp, value, &longValue) == TCL_OK)
              return PyLong_FromLong(longValue);
          /* If there is an error in the long conversion,
             fall through to wideInt handling. */
      }
  
      if (value->typePtr == tkapp->IntType ||
          value->typePtr == tkapp->WideIntType) {
          result = fromWideIntObj(tkapp, value);
          if (result != NULL || PyErr_Occurred())
              return result;
          Tcl_ResetResult(interp);
          /* If there is an error in the wideInt conversion,
             fall through to bignum handling. */
      }
  
  #ifdef HAVE_LIBTOMMATH
      if (value->typePtr == tkapp->IntType ||
          value->typePtr == tkapp->WideIntType ||
          value->typePtr == tkapp->BignumType) {
          return fromBignumObj(tkapp, value);
      }
  #endif
  
      if (value->typePtr == tkapp->ListType) {
          int size;
          int i, status;
          PyObject *elem;
          Tcl_Obj *tcl_elem;
  
          status = Tcl_ListObjLength(interp, value, &size);
          if (status == TCL_ERROR)
              return Tkinter_Error(tkapp);
          result = PyTuple_New(size);
          if (!result)
              return NULL;
          for (i = 0; i < size; i++) {
              status = Tcl_ListObjIndex(interp, value, i, &tcl_elem);
              if (status == TCL_ERROR) {
                  Py_DECREF(result);
                  return Tkinter_Error(tkapp);
              }
              elem = FromObj(tkapp, tcl_elem);
              if (!elem) {
                  Py_DECREF(result);
                  return NULL;
              }
              PyTuple_SET_ITEM(result, i, elem);
          }
          return result;
      }
  
      if (value->typePtr == tkapp->ProcBodyType) {
        /* fall through: return tcl object. */
      }
  
      if (value->typePtr == tkapp->StringType) {
          return unicodeFromTclObj(value);
      }
  
  #if TK_HEX_VERSION >= 0x08050000
      if (tkapp->BooleanType == NULL &&
          strcmp(value->typePtr->name, "booleanString") == 0) {
          /* booleanString type is not registered in Tcl */
          tkapp->BooleanType = value->typePtr;
          return fromBoolean(tkapp, value);
      }
  #endif
  
  #ifdef HAVE_LIBTOMMATH
      if (tkapp->BignumType == NULL &&
          strcmp(value->typePtr->name, "bignum") == 0) {
          /* bignum type is not registered in Tcl */
          tkapp->BignumType = value->typePtr;
          return fromBignumObj(tkapp, value);
      }
  #endif
  
      return newPyTclObject(value);
  }
  
  /* This mutex synchronizes inter-thread command calls. */
  TCL_DECLARE_MUTEX(call_mutex)
  
  typedef struct Tkapp_CallEvent {
      Tcl_Event ev;            /* Must be first */
      TkappObject *self;
      PyObject *args;
      int flags;
      PyObject **res;
      PyObject **exc_type, **exc_value, **exc_tb;
      Tcl_Condition *done;
  } Tkapp_CallEvent;
  
  void
  Tkapp_CallDeallocArgs(Tcl_Obj** objv, Tcl_Obj** objStore, int objc)
  {
      int i;
      for (i = 0; i < objc; i++)
          Tcl_DecrRefCount(objv[i]);
      if (objv != objStore)
          PyMem_Free(objv);
  }
  
  /* Convert Python objects to Tcl objects. This must happen in the
     interpreter thread, which may or may not be the calling thread. */
  
  static Tcl_Obj**
  Tkapp_CallArgs(PyObject *args, Tcl_Obj** objStore, int *pobjc)
  {
      Tcl_Obj **objv = objStore;
      Py_ssize_t objc = 0, i;
      if (args == NULL)
          /* do nothing */;
  
      else if (!(PyTuple_Check(args) || PyList_Check(args))) {
          objv[0] = AsObj(args);
          if (objv[0] == NULL)
              goto finally;
          objc = 1;
          Tcl_IncrRefCount(objv[0]);
      }
      else {
          objc = PySequence_Fast_GET_SIZE(args);
  
          if (objc > ARGSZ) {
              if (!CHECK_SIZE(objc, sizeof(Tcl_Obj *))) {
                  PyErr_SetString(PyExc_OverflowError,
                                  PyTuple_Check(args) ? "tuple is too long" :
                                                        "list is too long");
                  return NULL;
              }
              objv = (Tcl_Obj **)PyMem_Malloc(((size_t)objc) * sizeof(Tcl_Obj *));
              if (objv == NULL) {
                  PyErr_NoMemory();
                  objc = 0;
                  goto finally;
              }
          }
  
          for (i = 0; i < objc; i++) {
              PyObject *v = PySequence_Fast_GET_ITEM(args, i);
              if (v == Py_None) {
                  objc = i;
                  break;
              }
              objv[i] = AsObj(v);
              if (!objv[i]) {
                  /* Reset objc, so it attempts to clear
                     objects only up to i. */
                  objc = i;
                  goto finally;
              }
              Tcl_IncrRefCount(objv[i]);
          }
      }
      *pobjc = (int)objc;
      return objv;
  finally:
      Tkapp_CallDeallocArgs(objv, objStore, (int)objc);
      return NULL;
  }
  
  /* Convert the results of a command call into a Python string. */
  
  static PyObject *
  Tkapp_UnicodeResult(TkappObject *self)
  {
      return unicodeFromTclObj(Tcl_GetObjResult(self->interp));
  }
  
  
  /* Convert the results of a command call into a Python objects. */
  
  static PyObject *
  Tkapp_ObjectResult(TkappObject *self)
  {
      PyObject *res = NULL;
      Tcl_Obj *value = Tcl_GetObjResult(self->interp);
      if (self->wantobjects) {
          /* Not sure whether the IncrRef is necessary, but something
             may overwrite the interpreter result while we are
             converting it. */
          Tcl_IncrRefCount(value);
          res = FromObj(self, value);
          Tcl_DecrRefCount(value);
      } else {
          res = unicodeFromTclObj(value);
      }
      return res;
  }
  
  
  /* Tkapp_CallProc is the event procedure that is executed in the context of
     the Tcl interpreter thread. Initially, it holds the Tcl lock, and doesn't
     hold the Python lock. */
  
  static int
  Tkapp_CallProc(Tkapp_CallEvent *e, int flags)
  {
      Tcl_Obj *objStore[ARGSZ];
      Tcl_Obj **objv;
      int objc;
      int i;
      ENTER_PYTHON
      objv = Tkapp_CallArgs(e->args, objStore, &objc);
      if (!objv) {
          PyErr_Fetch(e->exc_type, e->exc_value, e->exc_tb);
          *(e->res) = NULL;
      }
      LEAVE_PYTHON
      if (!objv)
          goto done;
      i = Tcl_EvalObjv(e->self->interp, objc, objv, e->flags);
      ENTER_PYTHON
      if (i == TCL_ERROR) {
          *(e->res) = Tkinter_Error(e->self);
      }
      else {
          *(e->res) = Tkapp_ObjectResult(e->self);
      }
      if (*(e->res) == NULL) {
          PyErr_Fetch(e->exc_type, e->exc_value, e->exc_tb);
      }
      LEAVE_PYTHON
  
      Tkapp_CallDeallocArgs(objv, objStore, objc);
  done:
      /* Wake up calling thread. */
      Tcl_MutexLock(&call_mutex);
      Tcl_ConditionNotify(e->done);
      Tcl_MutexUnlock(&call_mutex);
      return 1;
  }
  
  
  /* This is the main entry point for calling a Tcl command.
     It supports three cases, with regard to threading:
     1. Tcl is not threaded: Must have the Tcl lock, then can invoke command in
        the context of the calling thread.
     2. Tcl is threaded, caller of the command is in the interpreter thread:
        Execute the command in the calling thread. Since the Tcl lock will
        not be used, we can merge that with case 1.
     3. Tcl is threaded, caller is in a different thread: Must queue an event to
        the interpreter thread. Allocation of Tcl objects needs to occur in the
        interpreter thread, so we ship the PyObject* args to the target thread,
        and perform processing there. */
  
  static PyObject *
  Tkapp_Call(PyObject *selfptr, PyObject *args)
  {
      Tcl_Obj *objStore[ARGSZ];
      Tcl_Obj **objv = NULL;
      int objc, i;
      PyObject *res = NULL;
      TkappObject *self = (TkappObject*)selfptr;
      int flags = TCL_EVAL_DIRECT | TCL_EVAL_GLOBAL;
  
      /* If args is a single tuple, replace with contents of tuple */
      if (PyTuple_GET_SIZE(args) == 1) {
          PyObject *item = PyTuple_GET_ITEM(args, 0);
          if (PyTuple_Check(item))
              args = item;
      }
      if (self->threaded && self->thread_id != Tcl_GetCurrentThread()) {
          /* We cannot call the command directly. Instead, we must
             marshal the parameters to the interpreter thread. */
          Tkapp_CallEvent *ev;
          Tcl_Condition cond = NULL;
          PyObject *exc_type, *exc_value, *exc_tb;
          if (!WaitForMainloop(self))
              return NULL;
          ev = (Tkapp_CallEvent*)attemptckalloc(sizeof(Tkapp_CallEvent));
          if (ev == NULL) {
              PyErr_NoMemory();
              return NULL;
          }
          ev->ev.proc = (Tcl_EventProc*)Tkapp_CallProc;
          ev->self = self;
          ev->args = args;
          ev->res = &res;
          ev->exc_type = &exc_type;
          ev->exc_value = &exc_value;
          ev->exc_tb = &exc_tb;
          ev->done = &cond;
  
          Tkapp_ThreadSend(self, (Tcl_Event*)ev, &cond, &call_mutex);
  
          if (res == NULL) {
              if (exc_type)
                  PyErr_Restore(exc_type, exc_value, exc_tb);
              else
                  PyErr_SetObject(Tkinter_TclError, exc_value);
          }
          Tcl_ConditionFinalize(&cond);
      }
      else
      {
  
          objv = Tkapp_CallArgs(args, objStore, &objc);
          if (!objv)
              return NULL;
  
          ENTER_TCL
  
          i = Tcl_EvalObjv(self->interp, objc, objv, flags);
  
          ENTER_OVERLAP
  
          if (i == TCL_ERROR)
              Tkinter_Error(self);
          else
              res = Tkapp_ObjectResult(self);
  
          LEAVE_OVERLAP_TCL
  
          Tkapp_CallDeallocArgs(objv, objStore, objc);
      }
      return res;
  }
  
  
  /*[clinic input]
  _tkinter.tkapp.eval
  
      script: str
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_eval_impl(TkappObject *self, const char *script)
  /*[clinic end generated code: output=24b79831f700dea0 input=481484123a455f22]*/
  {
      PyObject *res = NULL;
      int err;
  
      CHECK_STRING_LENGTH(script);
      CHECK_TCL_APPARTMENT;
  
      ENTER_TCL
      err = Tcl_Eval(Tkapp_Interp(self), script);
      ENTER_OVERLAP
      if (err == TCL_ERROR)
          res = Tkinter_Error(self);
      else
          res = Tkapp_UnicodeResult(self);
      LEAVE_OVERLAP_TCL
      return res;
  }
  
  /*[clinic input]
  _tkinter.tkapp.evalfile
  
      fileName: str
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_evalfile_impl(TkappObject *self, const char *fileName)
  /*[clinic end generated code: output=63be88dcee4f11d3 input=873ab707e5e947e1]*/
  {
      PyObject *res = NULL;
      int err;
  
      CHECK_STRING_LENGTH(fileName);
      CHECK_TCL_APPARTMENT;
  
      ENTER_TCL
      err = Tcl_EvalFile(Tkapp_Interp(self), fileName);
      ENTER_OVERLAP
      if (err == TCL_ERROR)
          res = Tkinter_Error(self);
      else
          res = Tkapp_UnicodeResult(self);
      LEAVE_OVERLAP_TCL
      return res;
  }
  
  /*[clinic input]
  _tkinter.tkapp.record
  
      script: str
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_record_impl(TkappObject *self, const char *script)
  /*[clinic end generated code: output=0ffe08a0061730df input=c0b0db5a21412cac]*/
  {
      PyObject *res = NULL;
      int err;
  
      CHECK_STRING_LENGTH(script);
      CHECK_TCL_APPARTMENT;
  
      ENTER_TCL
      err = Tcl_RecordAndEval(Tkapp_Interp(self), script, TCL_NO_EVAL);
      ENTER_OVERLAP
      if (err == TCL_ERROR)
          res = Tkinter_Error(self);
      else
          res = Tkapp_UnicodeResult(self);
      LEAVE_OVERLAP_TCL
      return res;
  }
  
  /*[clinic input]
  _tkinter.tkapp.adderrorinfo
  
      msg: str
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_adderrorinfo_impl(TkappObject *self, const char *msg)
  /*[clinic end generated code: output=52162eaca2ee53cb input=f4b37aec7c7e8c77]*/
  {
      CHECK_STRING_LENGTH(msg);
      CHECK_TCL_APPARTMENT;
  
      ENTER_TCL
      Tcl_AddErrorInfo(Tkapp_Interp(self), msg);
      LEAVE_TCL
  
      Py_RETURN_NONE;
  }
  
  
  
  /** Tcl Variable **/
  
  typedef PyObject* (*EventFunc)(TkappObject *, PyObject *, int);
  
  TCL_DECLARE_MUTEX(var_mutex)
  
  typedef struct VarEvent {
      Tcl_Event ev; /* must be first */
      TkappObject *self;
      PyObject *args;
      int flags;
      EventFunc func;
      PyObject **res;
      PyObject **exc_type;
      PyObject **exc_val;
      Tcl_Condition *cond;
  } VarEvent;
  
  /*[python]
  
  class varname_converter(CConverter):
      type = 'const char *'
      converter = 'varname_converter'
  
  [python]*/
  /*[python checksum: da39a3ee5e6b4b0d3255bfef95601890afd80709]*/
  
  static int
  varname_converter(PyObject *in, void *_out)
  {
      const char *s;
      const char **out = (const char**)_out;
      if (PyBytes_Check(in)) {
          if (PyBytes_GET_SIZE(in) > INT_MAX) {
              PyErr_SetString(PyExc_OverflowError, "bytes object is too long");
              return 0;
          }
          s = PyBytes_AS_STRING(in);
          if (strlen(s) != (size_t)PyBytes_GET_SIZE(in)) {
              PyErr_SetString(PyExc_ValueError, "embedded null byte");
              return 0;
          }
          *out = s;
          return 1;
      }
      if (PyUnicode_Check(in)) {
          Py_ssize_t size;
          s = PyUnicode_AsUTF8AndSize(in, &size);
          if (s == NULL) {
              return 0;
          }
          if (size > INT_MAX) {
              PyErr_SetString(PyExc_OverflowError, "string is too long");
              return 0;
          }
          if (strlen(s) != (size_t)size) {
              PyErr_SetString(PyExc_ValueError, "embedded null character");
              return 0;
          }
          *out = s;
          return 1;
      }
      if (PyTclObject_Check(in)) {
          *out = Tcl_GetString(((PyTclObject *)in)->value);
          return 1;
      }
      PyErr_Format(PyExc_TypeError,
                   "must be str, bytes or Tcl_Obj, not %.50s",
                   Py_TYPE(in)->tp_name);
      return 0;
  }
  
  
  static void
  var_perform(VarEvent *ev)
  {
      *(ev->res) = ev->func(ev->self, ev->args, ev->flags);
      if (!*(ev->res)) {
          PyObject *exc, *val, *tb;
          PyErr_Fetch(&exc, &val, &tb);
          PyErr_NormalizeException(&exc, &val, &tb);
          *(ev->exc_type) = exc;
          *(ev->exc_val) = val;
          Py_XDECREF(tb);
      }
  
  }
  
  static int
  var_proc(VarEvent* ev, int flags)
  {
      ENTER_PYTHON
      var_perform(ev);
      Tcl_MutexLock(&var_mutex);
      Tcl_ConditionNotify(ev->cond);
      Tcl_MutexUnlock(&var_mutex);
      LEAVE_PYTHON
      return 1;
  }
  
  
  static PyObject*
  var_invoke(EventFunc func, PyObject *selfptr, PyObject *args, int flags)
  {
      TkappObject *self = (TkappObject*)selfptr;
      if (self->threaded && self->thread_id != Tcl_GetCurrentThread()) {
          VarEvent *ev;
          PyObject *res, *exc_type, *exc_val;
          Tcl_Condition cond = NULL;
  
          /* The current thread is not the interpreter thread.  Marshal
             the call to the interpreter thread, then wait for
             completion. */
          if (!WaitForMainloop(self))
              return NULL;
  
          ev = (VarEvent*)attemptckalloc(sizeof(VarEvent));
          if (ev == NULL) {
              PyErr_NoMemory();
              return NULL;
          }
          ev->self = self;
          ev->args = args;
          ev->flags = flags;
          ev->func = func;
          ev->res = &res;
          ev->exc_type = &exc_type;
          ev->exc_val = &exc_val;
          ev->cond = &cond;
          ev->ev.proc = (Tcl_EventProc*)var_proc;
          Tkapp_ThreadSend(self, (Tcl_Event*)ev, &cond, &var_mutex);
          Tcl_ConditionFinalize(&cond);
          if (!res) {
              PyErr_SetObject(exc_type, exc_val);
              Py_DECREF(exc_type);
              Py_DECREF(exc_val);
              return NULL;
          }
          return res;
      }
      /* Tcl is not threaded, or this is the interpreter thread. */
      return func(self, args, flags);
  }
  
  static PyObject *
  SetVar(TkappObject *self, PyObject *args, int flags)
  {
      const char *name1, *name2;
      PyObject *newValue;
      PyObject *res = NULL;
      Tcl_Obj *newval, *ok;
  
      switch (PyTuple_GET_SIZE(args)) {
      case 2:
          if (!PyArg_ParseTuple(args, "O&O:setvar",
                                varname_converter, &name1, &newValue))
              return NULL;
          /* XXX Acquire tcl lock??? */
          newval = AsObj(newValue);
          if (newval == NULL)
              return NULL;
          ENTER_TCL
          ok = Tcl_SetVar2Ex(Tkapp_Interp(self), name1, NULL,
                             newval, flags);
          ENTER_OVERLAP
          if (!ok)
              Tkinter_Error(self);
          else {
              res = Py_None;
              Py_INCREF(res);
          }
          LEAVE_OVERLAP_TCL
          break;
      case 3:
          if (!PyArg_ParseTuple(args, "ssO:setvar",
                                &name1, &name2, &newValue))
              return NULL;
          CHECK_STRING_LENGTH(name1);
          CHECK_STRING_LENGTH(name2);
          /* XXX must hold tcl lock already??? */
          newval = AsObj(newValue);
          ENTER_TCL
          ok = Tcl_SetVar2Ex(Tkapp_Interp(self), name1, name2, newval, flags);
          ENTER_OVERLAP
          if (!ok)
              Tkinter_Error(self);
          else {
              res = Py_None;
              Py_INCREF(res);
          }
          LEAVE_OVERLAP_TCL
          break;
      default:
          PyErr_SetString(PyExc_TypeError, "setvar requires 2 to 3 arguments");
          return NULL;
      }
      return res;
  }
  
  static PyObject *
  Tkapp_SetVar(PyObject *self, PyObject *args)
  {
      return var_invoke(SetVar, self, args, TCL_LEAVE_ERR_MSG);
  }
  
  static PyObject *
  Tkapp_GlobalSetVar(PyObject *self, PyObject *args)
  {
      return var_invoke(SetVar, self, args, TCL_LEAVE_ERR_MSG | TCL_GLOBAL_ONLY);
  }
  
  
  
  static PyObject *
  GetVar(TkappObject *self, PyObject *args, int flags)
  {
      const char *name1, *name2=NULL;
      PyObject *res = NULL;
      Tcl_Obj *tres;
  
      if (!PyArg_ParseTuple(args, "O&|s:getvar",
                            varname_converter, &name1, &name2))
          return NULL;
  
      CHECK_STRING_LENGTH(name2);
      ENTER_TCL
      tres = Tcl_GetVar2Ex(Tkapp_Interp(self), name1, name2, flags);
      ENTER_OVERLAP
      if (tres == NULL) {
          Tkinter_Error(self);
      } else {
          if (self->wantobjects) {
              res = FromObj(self, tres);
          }
          else {
              res = unicodeFromTclObj(tres);
          }
      }
      LEAVE_OVERLAP_TCL
      return res;
  }
  
  static PyObject *
  Tkapp_GetVar(PyObject *self, PyObject *args)
  {
      return var_invoke(GetVar, self, args, TCL_LEAVE_ERR_MSG);
  }
  
  static PyObject *
  Tkapp_GlobalGetVar(PyObject *self, PyObject *args)
  {
      return var_invoke(GetVar, self, args, TCL_LEAVE_ERR_MSG | TCL_GLOBAL_ONLY);
  }
  
  
  
  static PyObject *
  UnsetVar(TkappObject *self, PyObject *args, int flags)
  {
      char *name1, *name2=NULL;
      int code;
      PyObject *res = NULL;
  
      if (!PyArg_ParseTuple(args, "s|s:unsetvar", &name1, &name2))
          return NULL;
  
      CHECK_STRING_LENGTH(name1);
      CHECK_STRING_LENGTH(name2);
      ENTER_TCL
      code = Tcl_UnsetVar2(Tkapp_Interp(self), name1, name2, flags);
      ENTER_OVERLAP
      if (code == TCL_ERROR)
          res = Tkinter_Error(self);
      else {
          Py_INCREF(Py_None);
          res = Py_None;
      }
      LEAVE_OVERLAP_TCL
      return res;
  }
  
  static PyObject *
  Tkapp_UnsetVar(PyObject *self, PyObject *args)
  {
      return var_invoke(UnsetVar, self, args, TCL_LEAVE_ERR_MSG);
  }
  
  static PyObject *
  Tkapp_GlobalUnsetVar(PyObject *self, PyObject *args)
  {
      return var_invoke(UnsetVar, self, args,
                        TCL_LEAVE_ERR_MSG | TCL_GLOBAL_ONLY);
  }
  
  
  
  /** Tcl to Python **/
  
  /*[clinic input]
  _tkinter.tkapp.getint
  
      arg: object
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_getint(TkappObject *self, PyObject *arg)
  /*[clinic end generated code: output=88cf293fae307cfe input=034026997c5b91f8]*/
  {
      char *s;
      Tcl_Obj *value;
      PyObject *result;
  
      if (PyLong_Check(arg)) {
          Py_INCREF(arg);
          return arg;
      }
  
      if (PyTclObject_Check(arg)) {
          value = ((PyTclObject*)arg)->value;
          Tcl_IncrRefCount(value);
      }
      else {
          if (!PyArg_Parse(arg, "s:getint", &s))
              return NULL;
          CHECK_STRING_LENGTH(s);
          value = Tcl_NewStringObj(s, -1);
          if (value == NULL)
              return Tkinter_Error(self);
      }
      /* Don't use Tcl_GetInt() because it returns ambiguous result for value
         in ranges -2**32..-2**31-1 and 2**31..2**32-1 (on 32-bit platform).
  
         Prefer bignum because Tcl_GetWideIntFromObj returns ambiguous result for
         value in ranges -2**64..-2**63-1 and 2**63..2**64-1 (on 32-bit platform).
       */
  #ifdef HAVE_LIBTOMMATH
      result = fromBignumObj(self, value);
  #else
      result = fromWideIntObj(self, value);
  #endif
      Tcl_DecrRefCount(value);
      if (result != NULL || PyErr_Occurred())
          return result;
      return Tkinter_Error(self);
  }
  
  /*[clinic input]
  _tkinter.tkapp.getdouble
  
      arg: object
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_getdouble(TkappObject *self, PyObject *arg)
  /*[clinic end generated code: output=c52b138bd8b956b9 input=22015729ce9ef7f8]*/
  {
      char *s;
      double v;
  
      if (PyFloat_Check(arg)) {
          Py_INCREF(arg);
          return arg;
      }
  
      if (PyNumber_Check(arg)) {
          return PyNumber_Float(arg);
      }
  
      if (PyTclObject_Check(arg)) {
          if (Tcl_GetDoubleFromObj(Tkapp_Interp(self),
                                   ((PyTclObject*)arg)->value,
                                   &v) == TCL_ERROR)
              return Tkinter_Error(self);
          return PyFloat_FromDouble(v);
      }
  
      if (!PyArg_Parse(arg, "s:getdouble", &s))
          return NULL;
      CHECK_STRING_LENGTH(s);
      if (Tcl_GetDouble(Tkapp_Interp(self), s, &v) == TCL_ERROR)
          return Tkinter_Error(self);
      return PyFloat_FromDouble(v);
  }
  
  /*[clinic input]
  _tkinter.tkapp.getboolean
  
      arg: object
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_getboolean(TkappObject *self, PyObject *arg)
  /*[clinic end generated code: output=726a9ae445821d91 input=7f11248ef8f8776e]*/
  {
      char *s;
      int v;
  
      if (PyLong_Check(arg)) { /* int or bool */
          return PyBool_FromLong(Py_SIZE(arg) != 0);
      }
  
      if (PyTclObject_Check(arg)) {
          if (Tcl_GetBooleanFromObj(Tkapp_Interp(self),
                                    ((PyTclObject*)arg)->value,
                                    &v) == TCL_ERROR)
              return Tkinter_Error(self);
          return PyBool_FromLong(v);
      }
  
      if (!PyArg_Parse(arg, "s:getboolean", &s))
          return NULL;
      CHECK_STRING_LENGTH(s);
      if (Tcl_GetBoolean(Tkapp_Interp(self), s, &v) == TCL_ERROR)
          return Tkinter_Error(self);
      return PyBool_FromLong(v);
  }
  
  /*[clinic input]
  _tkinter.tkapp.exprstring
  
      s: str
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_exprstring_impl(TkappObject *self, const char *s)
  /*[clinic end generated code: output=beda323d3ed0abb1 input=fa78f751afb2f21b]*/
  {
      PyObject *res = NULL;
      int retval;
  
      CHECK_STRING_LENGTH(s);
      CHECK_TCL_APPARTMENT;
  
      ENTER_TCL
      retval = Tcl_ExprString(Tkapp_Interp(self), s);
      ENTER_OVERLAP
      if (retval == TCL_ERROR)
          res = Tkinter_Error(self);
      else
          res = Tkapp_UnicodeResult(self);
      LEAVE_OVERLAP_TCL
      return res;
  }
  
  /*[clinic input]
  _tkinter.tkapp.exprlong
  
      s: str
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_exprlong_impl(TkappObject *self, const char *s)
  /*[clinic end generated code: output=5d6a46b63c6ebcf9 input=11bd7eee0c57b4dc]*/
  {
      PyObject *res = NULL;
      int retval;
      long v;
  
      CHECK_STRING_LENGTH(s);
      CHECK_TCL_APPARTMENT;
  
      ENTER_TCL
      retval = Tcl_ExprLong(Tkapp_Interp(self), s, &v);
      ENTER_OVERLAP
      if (retval == TCL_ERROR)
          res = Tkinter_Error(self);
      else
          res = PyLong_FromLong(v);
      LEAVE_OVERLAP_TCL
      return res;
  }
  
  /*[clinic input]
  _tkinter.tkapp.exprdouble
  
      s: str
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_exprdouble_impl(TkappObject *self, const char *s)
  /*[clinic end generated code: output=ff78df1081ea4158 input=ff02bc11798832d5]*/
  {
      PyObject *res = NULL;
      double v;
      int retval;
  
      CHECK_STRING_LENGTH(s);
      CHECK_TCL_APPARTMENT;
      ENTER_TCL
      retval = Tcl_ExprDouble(Tkapp_Interp(self), s, &v);
      ENTER_OVERLAP
      if (retval == TCL_ERROR)
          res = Tkinter_Error(self);
      else
          res = PyFloat_FromDouble(v);
      LEAVE_OVERLAP_TCL
      return res;
  }
  
  /*[clinic input]
  _tkinter.tkapp.exprboolean
  
      s: str
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_exprboolean_impl(TkappObject *self, const char *s)
  /*[clinic end generated code: output=8b28038c22887311 input=c8c66022bdb8d5d3]*/
  {
      PyObject *res = NULL;
      int retval;
      int v;
  
      CHECK_STRING_LENGTH(s);
      CHECK_TCL_APPARTMENT;
      ENTER_TCL
      retval = Tcl_ExprBoolean(Tkapp_Interp(self), s, &v);
      ENTER_OVERLAP
      if (retval == TCL_ERROR)
          res = Tkinter_Error(self);
      else
          res = PyLong_FromLong(v);
      LEAVE_OVERLAP_TCL
      return res;
  }
  
  
  
  /*[clinic input]
  _tkinter.tkapp.splitlist
  
      arg: object
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_splitlist(TkappObject *self, PyObject *arg)
  /*[clinic end generated code: output=13b51d34386d36fb input=2b2e13351e3c0b53]*/
  {
      char *list;
      int argc;
      const char **argv;
      PyObject *v;
      int i;
  
      if (PyTclObject_Check(arg)) {
          int objc;
          Tcl_Obj **objv;
          if (Tcl_ListObjGetElements(Tkapp_Interp(self),
                                     ((PyTclObject*)arg)->value,
                                     &objc, &objv) == TCL_ERROR) {
              return Tkinter_Error(self);
          }
          if (!(v = PyTuple_New(objc)))
              return NULL;
          for (i = 0; i < objc; i++) {
              PyObject *s = FromObj(self, objv[i]);
              if (!s) {
                  Py_DECREF(v);
                  return NULL;
              }
              PyTuple_SET_ITEM(v, i, s);
          }
          return v;
      }
      if (PyTuple_Check(arg)) {
          Py_INCREF(arg);
          return arg;
      }
      if (PyList_Check(arg)) {
          return PySequence_Tuple(arg);
      }
  
      if (!PyArg_Parse(arg, "et:splitlist", "utf-8", &list))
          return NULL;
  
      if (strlen(list) >= INT_MAX) {
          PyErr_SetString(PyExc_OverflowError, "string is too long");
          PyMem_Free(list);
          return NULL;
      }
      if (Tcl_SplitList(Tkapp_Interp(self), list,
                        &argc, &argv) == TCL_ERROR)  {
          PyMem_Free(list);
          return Tkinter_Error(self);
      }
  
      if (!(v = PyTuple_New(argc)))
          goto finally;
  
      for (i = 0; i < argc; i++) {
          PyObject *s = unicodeFromTclString(argv[i]);
          if (!s) {
              Py_DECREF(v);
              v = NULL;
              goto finally;
          }
          PyTuple_SET_ITEM(v, i, s);
      }
  
    finally:
      ckfree(FREECAST argv);
      PyMem_Free(list);
      return v;
  }
  
  /*[clinic input]
  _tkinter.tkapp.split
  
      arg: object
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_split(TkappObject *self, PyObject *arg)
  /*[clinic end generated code: output=e08ad832363facfd input=a1c78349eacaa140]*/
  {
      PyObject *v;
      char *list;
  
      if (PyErr_WarnEx(PyExc_DeprecationWarning,
              "split() is deprecated; consider using splitlist() instead", 1))
      {
          return NULL;
      }
  
      if (PyTclObject_Check(arg)) {
          Tcl_Obj *value = ((PyTclObject*)arg)->value;
          int objc;
          Tcl_Obj **objv;
          int i;
          if (Tcl_ListObjGetElements(Tkapp_Interp(self), value,
                                     &objc, &objv) == TCL_ERROR) {
              return FromObj(self, value);
          }
          if (objc == 0)
              return PyUnicode_FromString("");
          if (objc == 1)
              return FromObj(self, objv[0]);
          if (!(v = PyTuple_New(objc)))
              return NULL;
          for (i = 0; i < objc; i++) {
              PyObject *s = FromObj(self, objv[i]);
              if (!s) {
                  Py_DECREF(v);
                  return NULL;
              }
              PyTuple_SET_ITEM(v, i, s);
          }
          return v;
      }
      if (PyTuple_Check(arg) || PyList_Check(arg))
          return SplitObj(arg);
  
      if (!PyArg_Parse(arg, "et:split", "utf-8", &list))
          return NULL;
      if (strlen(list) >= INT_MAX) {
          PyErr_SetString(PyExc_OverflowError, "string is too long");
          PyMem_Free(list);
          return NULL;
      }
      v = Split(list);
      PyMem_Free(list);
      return v;
  }
  
  
  
  /** Tcl Command **/
  
  /* Client data struct */
  typedef struct {
      PyObject *self;
      PyObject *func;
  } PythonCmd_ClientData;
  
  static int
  PythonCmd_Error(Tcl_Interp *interp)
  {
      errorInCmd = 1;
      PyErr_Fetch(&excInCmd, &valInCmd, &trbInCmd);
      LEAVE_PYTHON
      return TCL_ERROR;
  }
  
  /* This is the Tcl command that acts as a wrapper for Python
   * function or method.
   */
  static int
  PythonCmd(ClientData clientData, Tcl_Interp *interp,
            int objc, Tcl_Obj *const objv[])
  {
      PythonCmd_ClientData *data = (PythonCmd_ClientData *)clientData;
      PyObject *args, *res;
      int i;
      Tcl_Obj *obj_res;
  
      ENTER_PYTHON
  
      /* Create argument tuple (objv1, ..., objvN) */
      if (!(args = PyTuple_New(objc - 1)))
          return PythonCmd_Error(interp);
  
      for (i = 0; i < (objc - 1); i++) {
          PyObject *s = unicodeFromTclObj(objv[i + 1]);
          if (!s) {
              Py_DECREF(args);
              return PythonCmd_Error(interp);
          }
          PyTuple_SET_ITEM(args, i, s);
      }
  
      res = PyObject_Call(data->func, args, NULL);
      Py_DECREF(args);
  
      if (res == NULL)
          return PythonCmd_Error(interp);
  
      obj_res = AsObj(res);
      if (obj_res == NULL) {
          Py_DECREF(res);
          return PythonCmd_Error(interp);
      }
      Tcl_SetObjResult(interp, obj_res);
      Py_DECREF(res);
  
      LEAVE_PYTHON
  
      return TCL_OK;
  }
  
  
  static void
  PythonCmdDelete(ClientData clientData)
  {
      PythonCmd_ClientData *data = (PythonCmd_ClientData *)clientData;
  
      ENTER_PYTHON
      Py_XDECREF(data->self);
      Py_XDECREF(data->func);
      PyMem_DEL(data);
      LEAVE_PYTHON
  }
  
  
  
  
  TCL_DECLARE_MUTEX(command_mutex)
  
  typedef struct CommandEvent{
      Tcl_Event ev;
      Tcl_Interp* interp;
      const char *name;
      int create;
      int *status;
      ClientData *data;
      Tcl_Condition *done;
  } CommandEvent;
  
  static int
  Tkapp_CommandProc(CommandEvent *ev, int flags)
  {
      if (ev->create)
          *ev->status = Tcl_CreateObjCommand(
              ev->interp, ev->name, PythonCmd,
              ev->data, PythonCmdDelete) == NULL;
      else
          *ev->status = Tcl_DeleteCommand(ev->interp, ev->name);
      Tcl_MutexLock(&command_mutex);
      Tcl_ConditionNotify(ev->done);
      Tcl_MutexUnlock(&command_mutex);
      return 1;
  }
  
  /*[clinic input]
  _tkinter.tkapp.createcommand
  
      name: str
      func: object
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_createcommand_impl(TkappObject *self, const char *name,
                                    PyObject *func)
  /*[clinic end generated code: output=2a1c79a4ee2af410 input=255785cb70edc6a0]*/
  {
      PythonCmd_ClientData *data;
      int err;
  
      CHECK_STRING_LENGTH(name);
      if (!PyCallable_Check(func)) {
          PyErr_SetString(PyExc_TypeError, "command not callable");
          return NULL;
      }
  
      if (self->threaded && self->thread_id != Tcl_GetCurrentThread() &&
          !WaitForMainloop(self))
          return NULL;
  
      data = PyMem_NEW(PythonCmd_ClientData, 1);
      if (!data)
          return PyErr_NoMemory();
      Py_INCREF(self);
      Py_INCREF(func);
      data->self = (PyObject *) self;
      data->func = func;
      if (self->threaded && self->thread_id != Tcl_GetCurrentThread()) {
          Tcl_Condition cond = NULL;
          CommandEvent *ev = (CommandEvent*)attemptckalloc(sizeof(CommandEvent));
          if (ev == NULL) {
              PyErr_NoMemory();
              PyMem_DEL(data);
              return NULL;
          }
          ev->ev.proc = (Tcl_EventProc*)Tkapp_CommandProc;
          ev->interp = self->interp;
          ev->create = 1;
          ev->name = name;
          ev->data = (ClientData)data;
          ev->status = &err;
          ev->done = &cond;
          Tkapp_ThreadSend(self, (Tcl_Event*)ev, &cond, &command_mutex);
          Tcl_ConditionFinalize(&cond);
      }
      else
      {
          ENTER_TCL
          err = Tcl_CreateObjCommand(
              Tkapp_Interp(self), name, PythonCmd,
              (ClientData)data, PythonCmdDelete) == NULL;
          LEAVE_TCL
      }
      if (err) {
          PyErr_SetString(Tkinter_TclError, "can't create Tcl command");
          PyMem_DEL(data);
          return NULL;
      }
  
      Py_RETURN_NONE;
  }
  
  
  
  /*[clinic input]
  _tkinter.tkapp.deletecommand
  
      name: str
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_deletecommand_impl(TkappObject *self, const char *name)
  /*[clinic end generated code: output=a67e8cb5845e0d2d input=53e9952eae1f85f5]*/
  {
      int err;
  
      CHECK_STRING_LENGTH(name);
  
      if (self->threaded && self->thread_id != Tcl_GetCurrentThread()) {
          Tcl_Condition cond = NULL;
          CommandEvent *ev;
          ev = (CommandEvent*)attemptckalloc(sizeof(CommandEvent));
          if (ev == NULL) {
              PyErr_NoMemory();
              return NULL;
          }
          ev->ev.proc = (Tcl_EventProc*)Tkapp_CommandProc;
          ev->interp = self->interp;
          ev->create = 0;
          ev->name = name;
          ev->status = &err;
          ev->done = &cond;
          Tkapp_ThreadSend(self, (Tcl_Event*)ev, &cond,
                           &command_mutex);
          Tcl_ConditionFinalize(&cond);
      }
      else
      {
          ENTER_TCL
          err = Tcl_DeleteCommand(self->interp, name);
          LEAVE_TCL
      }
      if (err == -1) {
          PyErr_SetString(Tkinter_TclError, "can't delete Tcl command");
          return NULL;
      }
      Py_RETURN_NONE;
  }
  
  
  
  #ifdef HAVE_CREATEFILEHANDLER
  /** File Handler **/
  
  typedef struct _fhcdata {
      PyObject *func;
      PyObject *file;
      int id;
      struct _fhcdata *next;
  } FileHandler_ClientData;
  
  static FileHandler_ClientData *HeadFHCD;
  
  static FileHandler_ClientData *
  NewFHCD(PyObject *func, PyObject *file, int id)
  {
      FileHandler_ClientData *p;
      p = PyMem_NEW(FileHandler_ClientData, 1);
      if (p != NULL) {
          Py_XINCREF(func);
          Py_XINCREF(file);
          p->func = func;
          p->file = file;
          p->id = id;
          p->next = HeadFHCD;
          HeadFHCD = p;
      }
      return p;
  }
  
  static void
  DeleteFHCD(int id)
  {
      FileHandler_ClientData *p, **pp;
  
      pp = &HeadFHCD;
      while ((p = *pp) != NULL) {
          if (p->id == id) {
              *pp = p->next;
              Py_XDECREF(p->func);
              Py_XDECREF(p->file);
              PyMem_DEL(p);
          }
          else
              pp = &p->next;
      }
  }
  
  static void
  FileHandler(ClientData clientData, int mask)
  {
      FileHandler_ClientData *data = (FileHandler_ClientData *)clientData;
      PyObject *func, *file, *res;
  
      ENTER_PYTHON
      func = data->func;
      file = data->file;
  
      res = PyObject_CallFunction(func, "Oi", file, mask);
      if (res == NULL) {
          errorInCmd = 1;
          PyErr_Fetch(&excInCmd, &valInCmd, &trbInCmd);
      }
      Py_XDECREF(res);
      LEAVE_PYTHON
  }
  
  /*[clinic input]
  _tkinter.tkapp.createfilehandler
  
      file: object
      mask: int
      func: object
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_createfilehandler_impl(TkappObject *self, PyObject *file,
                                        int mask, PyObject *func)
  /*[clinic end generated code: output=f73ce82de801c353 input=84943a5286e47947]*/
  {
      FileHandler_ClientData *data;
      int tfile;
  
      CHECK_TCL_APPARTMENT;
  
      tfile = PyObject_AsFileDescriptor(file);
      if (tfile < 0)
          return NULL;
      if (!PyCallable_Check(func)) {
          PyErr_SetString(PyExc_TypeError, "bad argument list");
          return NULL;
      }
  
      data = NewFHCD(func, file, tfile);
      if (data == NULL)
          return NULL;
  
      /* Ought to check for null Tcl_File object... */
      ENTER_TCL
      Tcl_CreateFileHandler(tfile, mask, FileHandler, (ClientData) data);
      LEAVE_TCL
      Py_RETURN_NONE;
  }
  
  /*[clinic input]
  _tkinter.tkapp.deletefilehandler
  
      file: object
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_deletefilehandler(TkappObject *self, PyObject *file)
  /*[clinic end generated code: output=b53cc96ebf9476fd input=abbec19d66312e2a]*/
  {
      int tfile;
  
      CHECK_TCL_APPARTMENT;
  
      tfile = PyObject_AsFileDescriptor(file);
      if (tfile < 0)
          return NULL;
  
      DeleteFHCD(tfile);
  
      /* Ought to check for null Tcl_File object... */
      ENTER_TCL
      Tcl_DeleteFileHandler(tfile);
      LEAVE_TCL
      Py_RETURN_NONE;
  }
  #endif /* HAVE_CREATEFILEHANDLER */
  
  
  /**** Tktt Object (timer token) ****/
  
  static PyObject *Tktt_Type;
  
  typedef struct {
      PyObject_HEAD
      Tcl_TimerToken token;
      PyObject *func;
  } TkttObject;
  
  /*[clinic input]
  _tkinter.tktimertoken.deletetimerhandler
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tktimertoken_deletetimerhandler_impl(TkttObject *self)
  /*[clinic end generated code: output=bd7fe17f328cfa55 input=40bd070ff85f5cf3]*/
  {
      TkttObject *v = self;
      PyObject *func = v->func;
  
      if (v->token != NULL) {
          Tcl_DeleteTimerHandler(v->token);
          v->token = NULL;
      }
      if (func != NULL) {
          v->func = NULL;
          Py_DECREF(func);
          Py_DECREF(v); /* See Tktt_New() */
      }
      Py_RETURN_NONE;
  }
  
  static TkttObject *
  Tktt_New(PyObject *func)
  {
      TkttObject *v;
  
      v = PyObject_New(TkttObject, (PyTypeObject *) Tktt_Type);
      if (v == NULL)
          return NULL;
  
      Py_INCREF(func);
      v->token = NULL;
      v->func = func;
  
      /* Extra reference, deleted when called or when handler is deleted */
      Py_INCREF(v);
      return v;
  }
  
  static void
  Tktt_Dealloc(PyObject *self)
  {
      TkttObject *v = (TkttObject *)self;
      PyObject *func = v->func;
      PyObject *tp = (PyObject *) Py_TYPE(self);
  
      Py_XDECREF(func);
  
      PyObject_Del(self);
      Py_DECREF(tp);
  }
  
  static PyObject *
  Tktt_Repr(PyObject *self)
  {
      TkttObject *v = (TkttObject *)self;
      return PyUnicode_FromFormat("<tktimertoken at %p%s>",
                                  v,
                                  v->func == NULL ? ", handler deleted" : "");
  }
  
  /** Timer Handler **/
  
  static void
  TimerHandler(ClientData clientData)
  {
      TkttObject *v = (TkttObject *)clientData;
      PyObject *func = v->func;
      PyObject *res;
  
      if (func == NULL)
          return;
  
      v->func = NULL;
  
      ENTER_PYTHON
  
      res = PyObject_CallNoArgs(func);
      Py_DECREF(func);
      Py_DECREF(v); /* See Tktt_New() */
  
      if (res == NULL) {
          errorInCmd = 1;
          PyErr_Fetch(&excInCmd, &valInCmd, &trbInCmd);
      }
      else
          Py_DECREF(res);
  
      LEAVE_PYTHON
  }
  
  /*[clinic input]
  _tkinter.tkapp.createtimerhandler
  
      milliseconds: int
      func: object
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_createtimerhandler_impl(TkappObject *self, int milliseconds,
                                         PyObject *func)
  /*[clinic end generated code: output=2da5959b9d031911 input=ba6729f32f0277a5]*/
  {
      TkttObject *v;
  
      if (!PyCallable_Check(func)) {
          PyErr_SetString(PyExc_TypeError, "bad argument list");
          return NULL;
      }
  
      CHECK_TCL_APPARTMENT;
  
      v = Tktt_New(func);
      if (v) {
          v->token = Tcl_CreateTimerHandler(milliseconds, TimerHandler,
                                            (ClientData)v);
      }
  
      return (PyObject *) v;
  }
  
  
  /** Event Loop **/
  
  /*[clinic input]
  _tkinter.tkapp.mainloop
  
      threshold: int = 0
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_mainloop_impl(TkappObject *self, int threshold)
  /*[clinic end generated code: output=0ba8eabbe57841b0 input=036bcdcf03d5eca0]*/
  {
      PyThreadState *tstate = PyThreadState_Get();
  
      CHECK_TCL_APPARTMENT;
      self->dispatching = 1;
  
      quitMainLoop = 0;
      while (Tk_GetNumMainWindows() > threshold &&
             !quitMainLoop &&
             !errorInCmd)
      {
          int result;
  
          if (self->threaded) {
              /* Allow other Python threads to run. */
              ENTER_TCL
              result = Tcl_DoOneEvent(0);
              LEAVE_TCL
          }
          else {
              Py_BEGIN_ALLOW_THREADS
              if(tcl_lock)PyThread_acquire_lock(tcl_lock, 1);
              tcl_tstate = tstate;
              result = Tcl_DoOneEvent(TCL_DONT_WAIT);
              tcl_tstate = NULL;
              if(tcl_lock)PyThread_release_lock(tcl_lock);
              if (result == 0)
                  Sleep(Tkinter_busywaitinterval);
              Py_END_ALLOW_THREADS
          }
  
          if (PyErr_CheckSignals() != 0) {
              self->dispatching = 0;
              return NULL;
          }
          if (result < 0)
              break;
      }
      self->dispatching = 0;
      quitMainLoop = 0;
  
      if (errorInCmd) {
          errorInCmd = 0;
          PyErr_Restore(excInCmd, valInCmd, trbInCmd);
          excInCmd = valInCmd = trbInCmd = NULL;
          return NULL;
      }
      Py_RETURN_NONE;
  }
  
  /*[clinic input]
  _tkinter.tkapp.dooneevent
  
      flags: int = 0
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_dooneevent_impl(TkappObject *self, int flags)
  /*[clinic end generated code: output=27c6b2aa464cac29 input=6542b928e364b793]*/
  {
      int rv;
  
      ENTER_TCL
      rv = Tcl_DoOneEvent(flags);
      LEAVE_TCL
      return PyLong_FromLong(rv);
  }
  
  /*[clinic input]
  _tkinter.tkapp.quit
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_quit_impl(TkappObject *self)
  /*[clinic end generated code: output=7f21eeff481f754f input=e03020dc38aff23c]*/
  {
      quitMainLoop = 1;
      Py_RETURN_NONE;
  }
  
  /*[clinic input]
  _tkinter.tkapp.interpaddr
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_interpaddr_impl(TkappObject *self)
  /*[clinic end generated code: output=6caaae3273b3c95a input=2dd32cbddb55a111]*/
  {
      return PyLong_FromVoidPtr(Tkapp_Interp(self));
  }
  
  /*[clinic input]
  _tkinter.tkapp.loadtk
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_loadtk_impl(TkappObject *self)
  /*[clinic end generated code: output=e9e10a954ce46d2a input=b5e82afedd6354f0]*/
  {
      Tcl_Interp *interp = Tkapp_Interp(self);
      const char * _tk_exists = NULL;
      int err;
  
  #ifdef TKINTER_PROTECT_LOADTK
      /* Up to Tk 8.4.13, Tk_Init deadlocks on the second call when the
       * first call failed.
       * To avoid the deadlock, we just refuse the second call through
       * a static variable.
       */
      if (tk_load_failed) {
          PyErr_SetString(Tkinter_TclError, TKINTER_LOADTK_ERRMSG);
          return NULL;
      }
  #endif
  
      /* We want to guard against calling Tk_Init() multiple times */
      CHECK_TCL_APPARTMENT;
      ENTER_TCL
      err = Tcl_Eval(Tkapp_Interp(self), "info exists     tk_version");
      ENTER_OVERLAP
      if (err == TCL_ERROR) {
          /* This sets an exception, but we cannot return right
             away because we need to exit the overlap first. */
          Tkinter_Error(self);
      } else {
          _tk_exists = Tcl_GetStringResult(Tkapp_Interp(self));
      }
      LEAVE_OVERLAP_TCL
      if (err == TCL_ERROR) {
          return NULL;
      }
      if (_tk_exists == NULL || strcmp(_tk_exists, "1") != 0)     {
          if (Tk_Init(interp)             == TCL_ERROR) {
              Tkinter_Error(self);
  #ifdef TKINTER_PROTECT_LOADTK
              tk_load_failed = 1;
  #endif
              return NULL;
          }
      }
      Py_RETURN_NONE;
  }
  
  static PyObject *
  Tkapp_WantObjects(PyObject *self, PyObject *args)
  {
  
      int wantobjects = -1;
      if (!PyArg_ParseTuple(args, "|i:wantobjects", &wantobjects))
          return NULL;
      if (wantobjects == -1)
          return PyBool_FromLong(((TkappObject*)self)->wantobjects);
      ((TkappObject*)self)->wantobjects = wantobjects;
  
      Py_RETURN_NONE;
  }
  
  /*[clinic input]
  _tkinter.tkapp.willdispatch
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_tkapp_willdispatch_impl(TkappObject *self)
  /*[clinic end generated code: output=0e3f46d244642155 input=d88f5970843d6dab]*/
  {
      self->dispatching = 1;
  
      Py_RETURN_NONE;
  }
  
  
  /**** Tkapp Type Methods ****/
  
  static void
  Tkapp_Dealloc(PyObject *self)
  {
      PyObject *tp = (PyObject *) Py_TYPE(self);
      /*CHECK_TCL_APPARTMENT;*/
      ENTER_TCL
      Tcl_DeleteInterp(Tkapp_Interp(self));
      LEAVE_TCL
      PyObject_Del(self);
      Py_DECREF(tp);
      DisableEventHook();
  }
  
  
  
  /**** Tkinter Module ****/
  
  typedef struct {
      PyObject* tuple;
      Py_ssize_t size; /* current size */
      Py_ssize_t maxsize; /* allocated size */
  } FlattenContext;
  
  static int
  _bump(FlattenContext* context, Py_ssize_t size)
  {
      /* expand tuple to hold (at least) size new items.
         return true if successful, false if an exception was raised */
  
      Py_ssize_t maxsize = context->maxsize * 2;  /* never overflows */
  
      if (maxsize < context->size + size)
          maxsize = context->size + size;  /* never overflows */
  
      context->maxsize = maxsize;
  
      return _PyTuple_Resize(&context->tuple, maxsize) >= 0;
  }
  
  static int
  _flatten1(FlattenContext* context, PyObject* item, int depth)
  {
      /* add tuple or list to argument tuple (recursively) */
  
      Py_ssize_t i, size;
  
      if (depth > 1000) {
          PyErr_SetString(PyExc_ValueError,
                          "nesting too deep in _flatten");
          return 0;
      } else if (PyTuple_Check(item) || PyList_Check(item)) {
          size = PySequence_Fast_GET_SIZE(item);
          /* preallocate (assume no nesting) */
          if (context->size + size > context->maxsize &&
              !_bump(context, size))
              return 0;
          /* copy items to output tuple */
          for (i = 0; i < size; i++) {
              PyObject *o = PySequence_Fast_GET_ITEM(item, i);
              if (PyList_Check(o) || PyTuple_Check(o)) {
                  if (!_flatten1(context, o, depth + 1))
                      return 0;
              } else if (o != Py_None) {
                  if (context->size + 1 > context->maxsize &&
                      !_bump(context, 1))
                      return 0;
                  Py_INCREF(o);
                  PyTuple_SET_ITEM(context->tuple,
                                   context->size++, o);
              }
          }
      } else {
          PyErr_SetString(PyExc_TypeError, "argument must be sequence");
          return 0;
      }
      return 1;
  }
  
  /*[clinic input]
  _tkinter._flatten
  
      item: object
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter__flatten(PyObject *module, PyObject *item)
  /*[clinic end generated code: output=cad02a3f97f29862 input=6b9c12260aa1157f]*/
  {
      FlattenContext context;
  
      context.maxsize = PySequence_Size(item);
      if (context.maxsize < 0)
          return NULL;
      if (context.maxsize == 0)
          return PyTuple_New(0);
  
      context.tuple = PyTuple_New(context.maxsize);
      if (!context.tuple)
          return NULL;
  
      context.size = 0;
  
      if (!_flatten1(&context, item,0))
          return NULL;
  
      if (_PyTuple_Resize(&context.tuple, context.size))
          return NULL;
  
      return context.tuple;
  }
  
  /*[clinic input]
  _tkinter.create
  
      screenName: str(accept={str, NoneType}) = None
      baseName: str = ""
      className: str = "Tk"
      interactive: bool(accept={int}) = False
      wantobjects: bool(accept={int}) = False
      wantTk: bool(accept={int}) = True
          if false, then Tk_Init() doesn't get called
      sync: bool(accept={int}) = False
          if true, then pass -sync to wish
      use: str(accept={str, NoneType}) = None
          if not None, then pass -use to wish
      /
  
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_create_impl(PyObject *module, const char *screenName,
                       const char *baseName, const char *className,
                       int interactive, int wantobjects, int wantTk, int sync,
                       const char *use)
  /*[clinic end generated code: output=e3315607648e6bb4 input=da9b17ee7358d862]*/
  {
      /* XXX baseName is not used anymore;
       * try getting rid of it. */
      CHECK_STRING_LENGTH(screenName);
      CHECK_STRING_LENGTH(baseName);
      CHECK_STRING_LENGTH(className);
      CHECK_STRING_LENGTH(use);
  
      return (PyObject *) Tkapp_New(screenName, className,
                                    interactive, wantobjects, wantTk,
                                    sync, use);
  }
  
  /*[clinic input]
  _tkinter.setbusywaitinterval
  
      new_val: int
      /
  
  Set the busy-wait interval in milliseconds between successive calls to Tcl_DoOneEvent in a threaded Python interpreter.
  
  It should be set to a divisor of the maximum time between frames in an animation.
  [clinic start generated code]*/
  
  static PyObject *
  _tkinter_setbusywaitinterval_impl(PyObject *module, int new_val)
  /*[clinic end generated code: output=42bf7757dc2d0ab6 input=deca1d6f9e6dae47]*/
  {
      if (new_val < 0) {
          PyErr_SetString(PyExc_ValueError,
                          "busywaitinterval must be >= 0");
          return NULL;
      }
      Tkinter_busywaitinterval = new_val;
      Py_RETURN_NONE;
  }
  
  /*[clinic input]
  _tkinter.getbusywaitinterval -> int
  
  Return the current busy-wait interval between successive calls to Tcl_DoOneEvent in a threaded Python interpreter.
  [clinic start generated code]*/
  
  static int
  _tkinter_getbusywaitinterval_impl(PyObject *module)
  /*[clinic end generated code: output=23b72d552001f5c7 input=a695878d2d576a84]*/
  {
      return Tkinter_busywaitinterval;
  }
  
  #include "clinic/_tkinter.c.h"
  
  static PyMethodDef Tktt_methods[] =
  {
      _TKINTER_TKTIMERTOKEN_DELETETIMERHANDLER_METHODDEF
      {NULL, NULL}
  };
  
  static PyType_Slot Tktt_Type_slots[] = {
      {Py_tp_dealloc, Tktt_Dealloc},
      {Py_tp_repr, Tktt_Repr},
      {Py_tp_methods, Tktt_methods},
      {0, 0}
  };
  
  static PyType_Spec Tktt_Type_spec = {
      "_tkinter.tktimertoken",
      sizeof(TkttObject),
      0,
      Py_TPFLAGS_DEFAULT,
      Tktt_Type_slots,
  };
  
  
  /**** Tkapp Method List ****/
  
  static PyMethodDef Tkapp_methods[] =
  {
      _TKINTER_TKAPP_WILLDISPATCH_METHODDEF
      {"wantobjects",            Tkapp_WantObjects, METH_VARARGS},
      {"call",                   Tkapp_Call, METH_VARARGS},
      _TKINTER_TKAPP_EVAL_METHODDEF
      _TKINTER_TKAPP_EVALFILE_METHODDEF
      _TKINTER_TKAPP_RECORD_METHODDEF
      _TKINTER_TKAPP_ADDERRORINFO_METHODDEF
      {"setvar",                 Tkapp_SetVar, METH_VARARGS},
      {"globalsetvar",       Tkapp_GlobalSetVar, METH_VARARGS},
      {"getvar",       Tkapp_GetVar, METH_VARARGS},
      {"globalgetvar",       Tkapp_GlobalGetVar, METH_VARARGS},
      {"unsetvar",     Tkapp_UnsetVar, METH_VARARGS},
      {"globalunsetvar",     Tkapp_GlobalUnsetVar, METH_VARARGS},
      _TKINTER_TKAPP_GETINT_METHODDEF
      _TKINTER_TKAPP_GETDOUBLE_METHODDEF
      _TKINTER_TKAPP_GETBOOLEAN_METHODDEF
      _TKINTER_TKAPP_EXPRSTRING_METHODDEF
      _TKINTER_TKAPP_EXPRLONG_METHODDEF
      _TKINTER_TKAPP_EXPRDOUBLE_METHODDEF
      _TKINTER_TKAPP_EXPRBOOLEAN_METHODDEF
      _TKINTER_TKAPP_SPLITLIST_METHODDEF
      _TKINTER_TKAPP_SPLIT_METHODDEF
      _TKINTER_TKAPP_CREATECOMMAND_METHODDEF
      _TKINTER_TKAPP_DELETECOMMAND_METHODDEF
      _TKINTER_TKAPP_CREATEFILEHANDLER_METHODDEF
      _TKINTER_TKAPP_DELETEFILEHANDLER_METHODDEF
      _TKINTER_TKAPP_CREATETIMERHANDLER_METHODDEF
      _TKINTER_TKAPP_MAINLOOP_METHODDEF
      _TKINTER_TKAPP_DOONEEVENT_METHODDEF
      _TKINTER_TKAPP_QUIT_METHODDEF
      _TKINTER_TKAPP_INTERPADDR_METHODDEF
      _TKINTER_TKAPP_LOADTK_METHODDEF
      {NULL,                     NULL}
  };
  
  static PyType_Slot Tkapp_Type_slots[] = {
      {Py_tp_dealloc, Tkapp_Dealloc},
      {Py_tp_methods, Tkapp_methods},
      {0, 0}
  };
  
  
  static PyType_Spec Tkapp_Type_spec = {
      "_tkinter.tkapp",
      sizeof(TkappObject),
      0,
      Py_TPFLAGS_DEFAULT,
      Tkapp_Type_slots,
  };
  
  static PyMethodDef moduleMethods[] =
  {
      _TKINTER__FLATTEN_METHODDEF
      _TKINTER_CREATE_METHODDEF
      _TKINTER_SETBUSYWAITINTERVAL_METHODDEF
      _TKINTER_GETBUSYWAITINTERVAL_METHODDEF
      {NULL,                 NULL}
  };
  
  #ifdef WAIT_FOR_STDIN
  
  static int stdin_ready = 0;
  
  #ifndef MS_WINDOWS
  static void
  MyFileProc(void *clientData, int mask)
  {
      stdin_ready = 1;
  }
  #endif
  
  static PyThreadState *event_tstate = NULL;
  
  static int
  EventHook(void)
  {
  #ifndef MS_WINDOWS
      int tfile;
  #endif
      PyEval_RestoreThread(event_tstate);
      stdin_ready = 0;
      errorInCmd = 0;
  #ifndef MS_WINDOWS
      tfile = fileno(stdin);
      Tcl_CreateFileHandler(tfile, TCL_READABLE, MyFileProc, NULL);
  #endif
      while (!errorInCmd && !stdin_ready) {
          int result;
  #ifdef MS_WINDOWS
          if (_kbhit()) {
              stdin_ready = 1;
              break;
          }
  #endif
          Py_BEGIN_ALLOW_THREADS
          if(tcl_lock)PyThread_acquire_lock(tcl_lock, 1);
          tcl_tstate = event_tstate;
  
          result = Tcl_DoOneEvent(TCL_DONT_WAIT);
  
          tcl_tstate = NULL;
          if(tcl_lock)PyThread_release_lock(tcl_lock);
          if (result == 0)
              Sleep(Tkinter_busywaitinterval);
          Py_END_ALLOW_THREADS
  
          if (result < 0)
              break;
      }
  #ifndef MS_WINDOWS
      Tcl_DeleteFileHandler(tfile);
  #endif
      if (errorInCmd) {
          errorInCmd = 0;
          PyErr_Restore(excInCmd, valInCmd, trbInCmd);
          excInCmd = valInCmd = trbInCmd = NULL;
          PyErr_Print();
      }
      PyEval_SaveThread();
      return 0;
  }
  
  #endif
  
  static void
  EnableEventHook(void)
  {
  #ifdef WAIT_FOR_STDIN
      if (PyOS_InputHook == NULL) {
          event_tstate = PyThreadState_Get();
          PyOS_InputHook = EventHook;
      }
  #endif
  }
  
  static void
  DisableEventHook(void)
  {
  #ifdef WAIT_FOR_STDIN
      if (Tk_GetNumMainWindows() == 0 && PyOS_InputHook == EventHook) {
          PyOS_InputHook = NULL;
      }
  #endif
  }
  
  
  static struct PyModuleDef _tkintermodule = {
      PyModuleDef_HEAD_INIT,
      "_tkinter",
      NULL,
      -1,
      moduleMethods,
      NULL,
      NULL,
      NULL,
      NULL
  };
  
  PyMODINIT_FUNC
  PyInit__tkinter(void)
  {
    PyObject *m, *uexe, *cexe, *o;
  
      tcl_lock = PyThread_allocate_lock();
      if (tcl_lock == NULL)
          return NULL;
  
      m = PyModule_Create(&_tkintermodule);
      if (m == NULL)
          return NULL;
  
      o = PyErr_NewException("_tkinter.TclError", NULL, NULL);
      if (o == NULL) {
          Py_DECREF(m);
          return NULL;
      }
      Py_INCREF(o);
      if (PyModule_AddObject(m, "TclError", o)) {
          Py_DECREF(o);
          Py_DECREF(m);
          return NULL;
      }
      Tkinter_TclError = o;
  
      if (PyModule_AddIntConstant(m, "READABLE", TCL_READABLE)) {
          Py_DECREF(m);
          return NULL;
      }
      if (PyModule_AddIntConstant(m, "WRITABLE", TCL_WRITABLE)) {
          Py_DECREF(m);
          return NULL;
      }
      if (PyModule_AddIntConstant(m, "EXCEPTION", TCL_EXCEPTION)) {
          Py_DECREF(m);
          return NULL;
      }
      if (PyModule_AddIntConstant(m, "WINDOW_EVENTS", TCL_WINDOW_EVENTS)) {
          Py_DECREF(m);
          return NULL;
      }
      if (PyModule_AddIntConstant(m, "FILE_EVENTS", TCL_FILE_EVENTS)) {
          Py_DECREF(m);
          return NULL;
      }
      if (PyModule_AddIntConstant(m, "TIMER_EVENTS", TCL_TIMER_EVENTS)) {
          Py_DECREF(m);
          return NULL;
      }
      if (PyModule_AddIntConstant(m, "IDLE_EVENTS", TCL_IDLE_EVENTS)) {
          Py_DECREF(m);
          return NULL;
      }
      if (PyModule_AddIntConstant(m, "ALL_EVENTS", TCL_ALL_EVENTS)) {
          Py_DECREF(m);
          return NULL;
      }
      if (PyModule_AddIntConstant(m, "DONT_WAIT", TCL_DONT_WAIT)) {
          Py_DECREF(m);
          return NULL;
      }
      if (PyModule_AddStringConstant(m, "TK_VERSION", TK_VERSION)) {
          Py_DECREF(m);
          return NULL;
      }
      if (PyModule_AddStringConstant(m, "TCL_VERSION", TCL_VERSION)) {
          Py_DECREF(m);
          return NULL;
      }
  
      o = PyType_FromSpec(&Tkapp_Type_spec);
      if (o == NULL) {
          Py_DECREF(m);
          return NULL;
      }
      ((PyTypeObject *)o)->tp_new = NULL;
      if (PyModule_AddObject(m, "TkappType", o)) {
          Py_DECREF(o);
          Py_DECREF(m);
          return NULL;
      }
      Tkapp_Type = o;
  
      o = PyType_FromSpec(&Tktt_Type_spec);
      if (o == NULL) {
          Py_DECREF(m);
          return NULL;
      }
      ((PyTypeObject *)o)->tp_new = NULL;
      if (PyModule_AddObject(m, "TkttType", o)) {
          Py_DECREF(o);
          Py_DECREF(m);
          return NULL;
      }
      Tktt_Type = o;
  
      o = PyType_FromSpec(&PyTclObject_Type_spec);
      if (o == NULL) {
          Py_DECREF(m);
          return NULL;
      }
      ((PyTypeObject *)o)->tp_new = NULL;
      if (PyModule_AddObject(m, "Tcl_Obj", o)) {
          Py_DECREF(o);
          Py_DECREF(m);
          return NULL;
      }
      PyTclObject_Type = o;
  
  #ifdef TK_AQUA
      /* Tk_MacOSXSetupTkNotifier must be called before Tcl's subsystems
       * start waking up.  Note that Tcl_FindExecutable will do this, this
       * code must be above it! The original warning from
       * tkMacOSXAppInit.c is copied below.
       *
       * NB - You have to swap in the Tk Notifier BEFORE you start up the
       * Tcl interpreter for now.  It probably should work to do this
       * in the other order, but for now it doesn't seem to.
       *
       */
      Tk_MacOSXSetupTkNotifier();
  #endif
  
  
      /* This helps the dynamic loader; in Unicode aware Tcl versions
         it also helps Tcl find its encodings. */
      uexe = PyUnicode_FromWideChar(Py_GetProgramName(), -1);
      if (uexe) {
          cexe = PyUnicode_EncodeFSDefault(uexe);
          if (cexe) {
  #ifdef MS_WINDOWS
              int set_var = 0;
              PyObject *str_path;
              wchar_t *wcs_path;
              DWORD ret;
  
              ret = GetEnvironmentVariableW(L"TCL_LIBRARY", NULL, 0);
  
              if (!ret && GetLastError() == ERROR_ENVVAR_NOT_FOUND) {
                  str_path = _get_tcl_lib_path();
                  if (str_path == NULL && PyErr_Occurred()) {
                      Py_DECREF(m);
                      return NULL;
                  }
                  if (str_path != NULL) {
                      wcs_path = PyUnicode_AsWideCharString(str_path, NULL);
                      if (wcs_path == NULL) {
                          Py_DECREF(m);
                          return NULL;
                      }
                      SetEnvironmentVariableW(L"TCL_LIBRARY", wcs_path);
                      set_var = 1;
                  }
              }
  
              Tcl_FindExecutable(PyBytes_AS_STRING(cexe));
  
              if (set_var) {
                  SetEnvironmentVariableW(L"TCL_LIBRARY", NULL);
                  PyMem_Free(wcs_path);
              }
  #else
              Tcl_FindExecutable(PyBytes_AS_STRING(cexe));
  #endif /* MS_WINDOWS */
          }
          Py_XDECREF(cexe);
          Py_DECREF(uexe);
      }
  
      if (PyErr_Occurred()) {
          Py_DECREF(m);
          return NULL;
      }
  
  #if 0
      /* This was not a good idea; through <Destroy> bindings,
         Tcl_Finalize() may invoke Python code but at that point the
         interpreter and thread state have already been destroyed! */
      Py_AtExit(Tcl_Finalize);
  #endif
      return m;
  }
  