int argc;              /* Number of original (expanded) arguments. */
  char **argv;           /* Full copy of the original (expanded) arguments. */
  void *library;         /* The Tcl library module handle. */
  void *xFindExecutable; /* See tcl_FindExecutableProc in th_tcl.c. */
  void *xCreateInterp;   /* See tcl_CreateInterpProc in th_tcl.c. */
  Tcl_Interp *interp;    /* The on-demand created Tcl interpreter. */
  char *setup;           /* The optional Tcl setup script. */
  void *xPreEval;        /* Optional, called before Tcl_Eval*(). */
  void *pPreContext;     /* Optional, provided to xPreEval(). */
  void *xPostEval;       /* Optional, called after Tcl_Eval*(). */
  void *pPostContext;    /* Optional, provided to xPostEval(). */
};
#endif

/*
** All global variables are in this structure.
*/
struct Global {

#    ifndef TCL_LIBRARY_NAME
#      define TCL_LIBRARY_NAME "tcl86.dll\0"
#    endif
#    ifndef TCL_MINOR_OFFSET
#      define TCL_MINOR_OFFSET (4)
#    endif
#    ifndef dlopen
#      define dlopen(a,b) (void *)LoadLibrary((a))
#    endif
#    ifndef dlsym
#      define dlsym(a,b) GetProcAddress((HANDLE)(a),(b))
#    endif
#    ifndef dlclose
#      define dlclose(a) FreeLibrary((HANDLE)(a))
#    endif
#  else
#    include <dlfcn.h>
#    if defined(__CYGWIN__)
#      ifndef TCL_LIBRARY_NAME
#        define TCL_LIBRARY_NAME "libtcl8.6.dll\0"
#      endif

#  endif
#  ifndef TCL_CREATEINTERP_NAME
#    define TCL_CREATEINTERP_NAME "_Tcl_CreateInterp"
#  endif
#endif /* defined(USE_TCL_STUBS) */

/*
** The function types for Tcl_FindExecutable and Tcl_CreateInterp are needed
** when the Tcl library is being loaded dynamically by a stubs-enabled
** application (i.e. the inverse of using a stubs-enabled package).  These are
** the only Tcl API functions that MUST be called prior to being able to call
** Tcl_InitStubs (i.e. because it requires a Tcl interpreter).
 */
typedef void (tcl_FindExecutableProc) (CONST char * argv0);
typedef Tcl_Interp *(tcl_CreateInterpProc) (void);

/*
** The function types for the "hook" functions to be called before and after a
** TH1 command makes a call to evaluate a Tcl script.  If the "pre" function
** returns anything but TH_OK, then evaluation of the Tcl script is skipped and
** that value is used as the return code.  If the "post" function returns
** anything other than its rc argument, that will become the new return code
** for the command.
 */
typedef int (tcl_NotifyProc) (
  void *pContext,    /* The context for this notification. */
  Th_Interp *interp, /* The TH1 interpreter being used. */
  void *ctx,         /* The original TH1 command context. */
  int argc,          /* Number of arguments for the TH1 command. */
  const char **argv, /* Array of arguments for the TH1 command. */
  int *argl,         /* Array of lengths for the TH1 command arguments. */
  int rc             /* Recommended notification return value. */
);

/*
** Creates and initializes a Tcl interpreter for use with the specified TH1
** interpreter.  Stores the created Tcl interpreter in the Tcl context supplied
** by the caller.  This must be declared here because quite a few functions in
** this file need to use it before it can be defined.
 */

  int argc;           /* Number of original arguments. */
  char **argv;        /* Full copy of the original arguments. */
  void *library;      /* The Tcl library module handle. */
  tcl_FindExecutableProc *xFindExecutable; /* Tcl_FindExecutable() pointer. */
  tcl_CreateInterpProc *xCreateInterp;     /* Tcl_CreateInterp() pointer. */
  Tcl_Interp *interp; /* The on-demand created Tcl interpreter. */
  char *setup;        /* The optional Tcl setup script. */
  tcl_NotifyProc *xPreEval;  /* Optional, called before Tcl_Eval*(). */
  void *pPreContext;         /* Optional, provided to xPreEval(). */
  tcl_NotifyProc *xPostEval; /* Optional, called after Tcl_Eval*(). */
  void *pPostContext;        /* Optional, provided to xPostEval(). */
};

/*
** This function calls the configured xPreEval or xPostEval functions, if any.
** May have arbitrary side-effects.  This function returns the result of the
** called notification function or the value of the rc argument if there is no
** notification function configured.
*/
static int notifyPreOrPostEval(
  int bIsPost,
  Th_Interp *interp,
  void *ctx,
  int argc,
  const char **argv,
  int *argl,
  int rc
){
  struct TclContext *tclContext = (struct TclContext *)ctx;
  tcl_NotifyProc *xNotifyProc;

  if ( !tclContext ){
    Th_ErrorMessage(interp,
        "Invalid Tcl context", (const char *)"", 0);
    return TH_ERROR;
  }
  xNotifyProc = bIsPost ? tclContext->xPostEval : tclContext->xPreEval;
  if ( xNotifyProc ){
    rc = xNotifyProc(bIsPost ?
        tclContext->pPostContext : tclContext->pPreContext,
        interp, ctx, argc, argv, argl, rc);
  }
  return rc;
}

/*
** Syntax:
**
**   tclEval arg ?arg ...?
*/
static int tclEval_command(
  Th_Interp *interp,
  void *ctx,
  int argc,
  const char **argv,
  int *argl
){
  Tcl_Interp *tclInterp;
  Tcl_Obj *objPtr;
  int rc = TH_OK;
  int nResult;
  const char *zResult;

  if( createTclInterp(interp, ctx)!=TH_OK ){
    return TH_ERROR;
  }
  if( argc<2 ){
    return Th_WrongNumArgs(interp, "tclEval arg ?arg ...?");
  }
  tclInterp = GET_CTX_TCL_INTERP(ctx);
  if( !tclInterp || Tcl_InterpDeleted(tclInterp) ){
    Th_ErrorMessage(interp, "invalid Tcl interpreter", (const char *)"", 0);
    return TH_ERROR;
  }
  rc = notifyPreOrPostEval(0, interp, ctx, argc, argv, argl, rc);
  if( rc!=TH_OK ){
    return rc;
  }
  Tcl_Preserve((ClientData)tclInterp);
  if( argc==2 ){
    objPtr = Tcl_NewStringObj(argv[1], argl[1]);
    Tcl_IncrRefCount(objPtr);
    rc = Tcl_EvalObjEx(tclInterp, objPtr, 0);
    Tcl_DecrRefCount(objPtr);
  }else{
    USE_ARGV_TO_OBJV();
    COPY_ARGV_TO_OBJV();
    objPtr = Tcl_ConcatObj(objc, objv);
    Tcl_IncrRefCount(objPtr);
    rc = Tcl_EvalObjEx(tclInterp, objPtr, 0);
    Tcl_DecrRefCount(objPtr);
    FREE_ARGV_TO_OBJV();
  }
  zResult = getTclResult(tclInterp, &nResult);
  Th_SetResult(interp, zResult, nResult);
  Tcl_Release((ClientData)tclInterp);
  rc = notifyPreOrPostEval(1, interp, ctx, argc, argv, argl, rc);
  return rc;
}

/*
** Syntax:
**
**   tclExpr arg ?arg ...?
*/
static int tclExpr_command(
  Th_Interp *interp,
  void *ctx,
  int argc,
  const char **argv,
  int *argl
){
  Tcl_Interp *tclInterp;
  Tcl_Obj *objPtr;
  Tcl_Obj *resultObjPtr;
  int rc = TH_OK;
  int nResult;
  const char *zResult;

  if( createTclInterp(interp, ctx)!=TH_OK ){
    return TH_ERROR;
  }
  if( argc<2 ){
    return Th_WrongNumArgs(interp, "tclExpr arg ?arg ...?");
  }
  tclInterp = GET_CTX_TCL_INTERP(ctx);
  if( !tclInterp || Tcl_InterpDeleted(tclInterp) ){
    Th_ErrorMessage(interp, "invalid Tcl interpreter", (const char *)"", 0);
    return TH_ERROR;
  }
  rc = notifyPreOrPostEval(0, interp, ctx, argc, argv, argl, rc);
  if( rc!=TH_OK ){
    return rc;
  }
  Tcl_Preserve((ClientData)tclInterp);
  if( argc==2 ){
    objPtr = Tcl_NewStringObj(argv[1], argl[1]);
    Tcl_IncrRefCount(objPtr);
    rc = Tcl_ExprObj(tclInterp, objPtr, &resultObjPtr);
    Tcl_DecrRefCount(objPtr);

    zResult = Tcl_GetStringFromObj(resultObjPtr, &nResult);
  }else{
    zResult = getTclResult(tclInterp, &nResult);
  }
  Th_SetResult(interp, zResult, nResult);
  if( rc==TCL_OK ) Tcl_DecrRefCount(resultObjPtr);
  Tcl_Release((ClientData)tclInterp);
  rc = notifyPreOrPostEval(1, interp, ctx, argc, argv, argl, rc);
  return rc;
}

/*
** Syntax:
**
**   tclInvoke command ?arg ...?
*/
static int tclInvoke_command(
  Th_Interp *interp,
  void *ctx,
  int argc,
  const char **argv,
  int *argl
){
  Tcl_Interp *tclInterp;
#if !defined(USE_TCL_EVALOBJV)
  Tcl_Command command;
  Tcl_CmdInfo cmdInfo;
#endif
  int rc = TH_OK;
  int nResult;
  const char *zResult;
#if !defined(USE_TCL_EVALOBJV)
  Tcl_Obj *objPtr;
#endif
  USE_ARGV_TO_OBJV();

  if( createTclInterp(interp, ctx)!=TH_OK ){
    return TH_ERROR;
  }
  if( argc<2 ){
    return Th_WrongNumArgs(interp, "tclInvoke command ?arg ...?");
  }
  tclInterp = GET_CTX_TCL_INTERP(ctx);
  if( !tclInterp || Tcl_InterpDeleted(tclInterp) ){
    Th_ErrorMessage(interp, "invalid Tcl interpreter", (const char *)"", 0);
    return TH_ERROR;
  }
  rc = notifyPreOrPostEval(0, interp, ctx, argc, argv, argl, rc);
  if( rc!=TH_OK ){
    return rc;
  }
  Tcl_Preserve((ClientData)tclInterp);
#if !defined(USE_TCL_EVALOBJV)
  objPtr = Tcl_NewStringObj(argv[1], argl[1]);
  Tcl_IncrRefCount(objPtr);
  command = Tcl_GetCommandFromObj(tclInterp, objPtr);
  if( !command || Tcl_GetCommandInfoFromToken(command,&cmdInfo)==0 ){

  Tcl_ResetResult(tclInterp);
  rc = cmdInfo.objProc(cmdInfo.objClientData, tclInterp, objc, objv);
#endif
  FREE_ARGV_TO_OBJV();
  zResult = getTclResult(tclInterp, &nResult);
  Th_SetResult(interp, zResult, nResult);
  Tcl_Release((ClientData)tclInterp);
  rc = notifyPreOrPostEval(1, interp, ctx, argc, argv, argl, rc);
  return rc;
}

/*
** Syntax:
**
**   th1Eval arg

<th1>
  #
  # This is a "TH1 fragment" used to test the Tcl integration features of TH1.
  # The corresponding test file executes this file using the test-th-render
  # Fossil command.
  #
  # NOTE: This test requires that the SQLite package be available for the Tcl
  #       interpreter that is linked to the Fossil executable.
  #
  tclInvoke set repository_name [repository 1]
  proc doOut {msg} {puts $msg; puts \n}
  doOut [tclEval {
    package require sqlite3
    sqlite3 db $repository_name -readonly true
    set x [db eval {SELECT COUNT(*) FROM user;}]
    db close
    return $x
  }]
</th1>