source: downloads/tcl8.5.2/win/tclWinLoad.c @ 47

/*
 * tclWinLoad.c --
 *
 *      This function provides a version of the TclLoadFile that works with
 *      the Windows "LoadLibrary" and "GetProcAddress" API for dynamic
 *      loading.
 *
 * Copyright (c) 1995-1997 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclWinLoad.c,v 1.20 2007/04/20 06:11:00 kennykb Exp $
 */

#include "tclWinInt.h"


/*
 *----------------------------------------------------------------------
 *
 * TclpDlopen --
 *
 *      Dynamically loads a binary code file into memory and returns a handle
 *      to the new code.
 *
 * Results:
 *      A standard Tcl completion code. If an error occurs, an error message
 *      is left in the interp's result.
 *
 * Side effects:
 *      New code suddenly appears in memory.
 *
 *----------------------------------------------------------------------
 */

int
TclpDlopen(
    Tcl_Interp *interp,         /* Used for error reporting. */
    Tcl_Obj *pathPtr,           /* Name of the file containing the desired
                                 * code (UTF-8). */
    Tcl_LoadHandle *loadHandle, /* Filled with token for dynamically loaded
                                 * file which will be passed back to
                                 * (*unloadProcPtr)() to unload the file. */
    Tcl_FSUnloadFileProc **unloadProcPtr)
                                /* Filled with address of Tcl_FSUnloadFileProc
                                 * function which should be used for this
                                 * file. */
{
    HINSTANCE handle;
    CONST TCHAR *nativeName;

    /*
     * First try the full path the user gave us. This is particularly
     * important if the cwd is inside a vfs, and we are trying to load using a
     * relative path.
     */

    nativeName = Tcl_FSGetNativePath(pathPtr);
    handle = (*tclWinProcs->loadLibraryProc)(nativeName);
    if (handle == NULL) {
        /*
         * Let the OS loader examine the binary search path for whatever
         * string the user gave us which hopefully refers to a file on the
         * binary path.
         */

        Tcl_DString ds;
        char *fileName = Tcl_GetString(pathPtr);

        nativeName = Tcl_WinUtfToTChar(fileName, -1, &ds);
        handle = (*tclWinProcs->loadLibraryProc)(nativeName);
        Tcl_DStringFree(&ds);
    }

    *loadHandle = (Tcl_LoadHandle) handle;

    if (handle == NULL) {
        DWORD lastError = GetLastError();

#if 0
        /*
         * It would be ideal if the FormatMessage stuff worked better, but
         * unfortunately it doesn't seem to want to...
         */

        LPTSTR lpMsgBuf;
        char *buf;
        int size;

        size = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM |
                FORMAT_MESSAGE_ALLOCATE_BUFFER, NULL, lastError, 0,
                (LPTSTR) &lpMsgBuf, 0, NULL);
        buf = (char *) ckalloc((unsigned) TCL_INTEGER_SPACE + size + 1);
        sprintf(buf, "%d %s", lastError, (char *)lpMsgBuf);
#endif

        Tcl_AppendResult(interp, "couldn't load library \"",
                Tcl_GetString(pathPtr), "\": ", NULL);

        /*
         * Check for possible DLL errors. This doesn't work quite right,
         * because Windows seems to only return ERROR_MOD_NOT_FOUND for just
         * about any problem, but it's better than nothing. It'd be even
         * better if there was a way to get what DLLs
         */

        switch (lastError) {
        case ERROR_MOD_NOT_FOUND:
        case ERROR_DLL_NOT_FOUND:
            Tcl_AppendResult(interp, "this library or a dependent library"
                    " could not be found in library path", NULL);
            break;
        case ERROR_PROC_NOT_FOUND:
            Tcl_AppendResult(interp, "A function specified in the import"
                    " table could not be resolved by the system.  Windows"
                    " is not telling which one, I'm sorry.", NULL);
            break;
        case ERROR_INVALID_DLL:
            Tcl_AppendResult(interp, "this library or a dependent library"
                    " is damaged", NULL);
            break;
        case ERROR_DLL_INIT_FAILED:
            Tcl_AppendResult(interp, "the library initialization"
                    " routine failed", NULL);
            break;
        default:
            TclWinConvertError(lastError);
            Tcl_AppendResult(interp, Tcl_PosixError(interp), NULL);
        }
        return TCL_ERROR;
    } else {
        *unloadProcPtr = &TclpUnloadFile;
    }
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpFindSymbol --
 *
 *      Looks up a symbol, by name, through a handle associated with a
 *      previously loaded piece of code (shared library).
 *
 * Results:
 *      Returns a pointer to the function associated with 'symbol' if it is
 *      found. Otherwise returns NULL and may leave an error message in the
 *      interp's result.
 *
 *----------------------------------------------------------------------
 */

Tcl_PackageInitProc *
TclpFindSymbol(
    Tcl_Interp *interp,
    Tcl_LoadHandle loadHandle,
    CONST char *symbol)
{
    Tcl_PackageInitProc *proc = NULL;
    HINSTANCE handle = (HINSTANCE)loadHandle;

    /*
     * For each symbol, check for both Symbol and _Symbol, since Borland
     * generates C symbols with a leading '_' by default.
     */

    proc = (Tcl_PackageInitProc *) GetProcAddress(handle, symbol);
    if (proc == NULL) {
        Tcl_DString ds;

        Tcl_DStringInit(&ds);
        Tcl_DStringAppend(&ds, "_", 1);
        symbol = Tcl_DStringAppend(&ds, symbol, -1);
        proc = (Tcl_PackageInitProc *) GetProcAddress(handle, symbol);
        Tcl_DStringFree(&ds);
    }
    return proc;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpUnloadFile --
 *
 *      Unloads a dynamically loaded binary code file from memory. Code
 *      pointers in the formerly loaded file are no longer valid after calling
 *      this function.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Code removed from memory.
 *
 *----------------------------------------------------------------------
 */

void
TclpUnloadFile(
    Tcl_LoadHandle loadHandle)  /* loadHandle returned by a previous call to
                                 * TclpDlopen(). The loadHandle is a token
                                 * that represents the loaded file. */
{
    HINSTANCE handle;

    handle = (HINSTANCE) loadHandle;
    FreeLibrary(handle);
}

/*
 *----------------------------------------------------------------------
 *
 * TclGuessPackageName --
 *
 *      If the "load" command is invoked without providing a package name,
 *      this function is invoked to try to figure it out.
 *
 * Results:
 *      Always returns 0 to indicate that we couldn't figure out a package
 *      name; generic code will then try to guess the package from the file
 *      name. A return value of 1 would have meant that we figured out the
 *      package name and put it in bufPtr.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

int
TclGuessPackageName(
    CONST char *fileName,       /* Name of file containing package (already
                                 * translated to local form if needed). */
    Tcl_DString *bufPtr)        /* Initialized empty dstring. Append package
                                 * name to this if possible. */
{
    return 0;
}

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */