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/*
 * tclStubLib.c --
 *
 *	Stub object that will be statically linked into extensions that want
 *	to access Tcl.
 *
 * Copyright (c) 1998-1999 by Scriptics Corporation.
 * Copyright (c) 1998 Paul Duffin.
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclStubLib.c,v 1.9 2005/11/02 14:51:05 dkf Exp $
 */

/*
 * We need to ensure that we use the stub macros so that this file contains no
 * references to any of the stub functions. This will make it possible to
 * build an extension that references Tcl_InitStubs but doesn't end up
 * including the rest of the stub functions.
 */

#ifndef USE_TCL_STUBS
#define USE_TCL_STUBS
#endif
#undef USE_TCL_STUB_PROCS

#include "tclInt.h"

/*
 * Ensure that Tcl_InitStubs is built as an exported symbol. The other stub
 * functions should be built as non-exported symbols.
 */

#undef TCL_STORAGE_CLASS
#define TCL_STORAGE_CLASS DLLEXPORT

TclStubs *tclStubsPtr = NULL;
TclPlatStubs *tclPlatStubsPtr = NULL;
TclIntStubs *tclIntStubsPtr = NULL;
TclIntPlatStubs *tclIntPlatStubsPtr = NULL;

static TclStubs *	HasStubSupport(Tcl_Interp *interp);

static TclStubs *
HasStubSupport(
    Tcl_Interp *interp)
{
    Interp *iPtr = (Interp *) interp;

    if (iPtr->stubTable && (iPtr->stubTable->magic == TCL_STUB_MAGIC)) {
	return iPtr->stubTable;
    }

    interp->result =
	    "This interpreter does not support stubs-enabled extensions.";
    interp->freeProc = TCL_STATIC;
    return NULL;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_InitStubs --
 *
 *	Tries to initialise the stub table pointers and ensures that the
 *	correct version of Tcl is loaded.
 *
 * Results:
 *	The actual version of Tcl that satisfies the request, or NULL to
 *	indicate that an error occurred.
 *
 * Side effects:
 *	Sets the stub table pointers.
 *
 *----------------------------------------------------------------------
 */

#ifdef Tcl_InitStubs
#undef Tcl_InitStubs
#endif

CONST char *
Tcl_InitStubs(
    Tcl_Interp *interp,
    CONST char *version,
    int exact)
{
    CONST char *actualVersion = NULL;
    TclStubs *tmp;
    TclStubs **tmpp;

    /*
     * We can't optimize this check by caching tclStubsPtr because that
     * prevents apps from being able to load/unload Tcl dynamically multiple
     * times. [Bug 615304]
     */

    tclStubsPtr = HasStubSupport(interp);
    if (!tclStubsPtr) {
	return NULL;
    }

    /*
     * This is needed to satisfy GCC 3.3's strict aliasing rules.
     */

    tmpp = &tmp;
    actualVersion = Tcl_PkgRequireEx(interp, "Tcl", version, exact,
	    (ClientData *) tmpp);
    if (actualVersion == NULL) {
	tclStubsPtr = NULL;
	return NULL;
    }

    if (tclStubsPtr->hooks) {
	tclPlatStubsPtr = tclStubsPtr->hooks->tclPlatStubs;
	tclIntStubsPtr = tclStubsPtr->hooks->tclIntStubs;
	tclIntPlatStubsPtr = tclStubsPtr->hooks->tclIntPlatStubs;
    } else {
	tclPlatStubsPtr = NULL;
	tclIntStubsPtr = NULL;
	tclIntPlatStubsPtr = NULL;
    }

    return actualVersion;
}

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */