www.pudn.com > mitab.rar > cplgetsymbol.cpp
/******************************************************************************
* $Id: cplgetsymbol.cpp,v 1.14 2004/11/11 20:40:38 fwarmerdam Exp $
*
* Project: Common Portability Library
* Purpose: Fetch a function pointer from a shared library / DLL.
* Author: Frank Warmerdam, warmerda@home.com
*
******************************************************************************
* Copyright (c) 1999, Frank Warmerdam
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
******************************************************************************
*
* $Log: cplgetsymbol.cpp,v $
* Revision 1.14 2004/11/11 20:40:38 fwarmerdam
* Check for variant of symbol with a leading underscore on Mach-O/Apple
* systems. Patch by John Hayes / Lizardtech.
* http://bugzilla.remotesensing.org/show_bug.cgi?id=668
*
* Revision 1.13 2003/08/26 01:08:04 warmerda
* Cast return result of GetProcAddress() for use with MingW.
*
* Revision 1.12 2002/11/20 17:16:48 warmerda
* Added debug report from dummy CPLGetSymbol().
*
* Revision 1.11 2001/07/18 04:00:49 warmerda
* added CPL_CVSID
*
* Revision 1.10 2001/01/19 21:16:41 warmerda
* expanded tabs
*
* Revision 1.9 2000/09/25 19:59:03 warmerda
* look for WIN32 not _WIN32
*
* Revision 1.8 1999/05/20 02:54:38 warmerda
* Added API documentation
*
* Revision 1.7 1999/04/23 13:56:36 warmerda
* added stub implementation. Don't check for __unix__
*
* Revision 1.6 1999/04/21 20:06:05 warmerda
* Removed incorrect comment.
*
* Revision 1.5 1999/03/02 21:20:00 warmerda
* test for dlfcn.h, not -ldl
*
* Revision 1.4 1999/03/02 21:08:11 warmerda
* autoconf switch
*
* Revision 1.3 1999/01/28 18:35:44 warmerda
* minor windows cleanup.
*
* Revision 1.2 1999/01/27 20:16:03 warmerda
* Added windows implementation.
*
* Revision 1.1 1999/01/11 15:34:57 warmerda
* New
*
*/
#include "cpl_conv.h"
CPL_CVSID("$Id: cplgetsymbol.cpp,v 1.14 2004/11/11 20:40:38 fwarmerdam Exp $");
/* ==================================================================== */
/* Unix Implementation */
/* ==================================================================== */
#if defined(HAVE_DLFCN_H)
#define GOT_GETSYMBOL
#include
/************************************************************************/
/* CPLGetSymbol() */
/************************************************************************/
/**
* Fetch a function pointer from a shared library / DLL.
*
* This function is meant to abstract access to shared libraries and
* DLLs and performs functions similar to dlopen()/dlsym() on Unix and
* LoadLibrary() / GetProcAddress() on Windows.
*
* If no support for loading entry points from a shared library is available
* this function will always return NULL. Rules on when this function
* issues a CPLError() or not are not currently well defined, and will have
* to be resolved in the future.
*
* Currently CPLGetSymbol() doesn't try to:
*
* - prevent the reference count on the library from going up
* for every request, or given any opportunity to unload
* the library.
*
- Attempt to look for the library in non-standard
* locations.
*
- Attempt to try variations on the symbol name, like
* pre-prending or post-pending an underscore.
*
*
* Some of these issues may be worked on in the future.
*
* @param pszLibrary the name of the shared library or DLL containing
* the function. May contain path to file. If not system supplies search
* paths will be used.
* @param pszSymbolName the name of the function to fetch a pointer to.
* @return A pointer to the function if found, or NULL if the function isn't
* found, or the shared library can't be loaded.
*/
void *CPLGetSymbol( const char * pszLibrary, const char * pszSymbolName )
{
void *pLibrary;
void *pSymbol;
pLibrary = dlopen(pszLibrary, RTLD_LAZY);
if( pLibrary == NULL )
{
CPLError( CE_Failure, CPLE_AppDefined,
"%s", dlerror() );
return NULL;
}
pSymbol = dlsym( pLibrary, pszSymbolName );
#if (defined(__APPLE__) && defined(__MACH__))
/* On mach-o systems, C symbols have a leading underscore and depending
* on how dlcompat is configured it may or may not add the leading
* underscore. So if dlsym() fails add an underscore and try again.
*/
if( pSymbol == NULL )
{
char withUnder[strlen(pszSymbolName) + 2];
withUnder[0] = '_'; withUnder[1] = 0;
strcat(withUnder, pszSymbolName);
pSymbol = dlsym( pLibrary, withUnder );
}
#endif
if( pSymbol == NULL )
{
CPLError( CE_Failure, CPLE_AppDefined,
"%s", dlerror() );
return NULL;
}
return( pSymbol );
}
#endif /* def __unix__ && defined(HAVE_DLFCN_H) */
/* ==================================================================== */
/* Windows Implementation */
/* ==================================================================== */
#ifdef WIN32
#define GOT_GETSYMBOL
#include
/************************************************************************/
/* CPLGetSymbol() */
/************************************************************************/
void *CPLGetSymbol( const char * pszLibrary, const char * pszSymbolName )
{
void *pLibrary;
void *pSymbol;
pLibrary = LoadLibrary(pszLibrary);
if( pLibrary == NULL )
{
CPLError( CE_Failure, CPLE_AppDefined,
"Can't load requested DLL: %s", pszLibrary );
return NULL;
}
pSymbol = (void *) GetProcAddress( (HINSTANCE) pLibrary, pszSymbolName );
if( pSymbol == NULL )
{
CPLError( CE_Failure, CPLE_AppDefined,
"Can't find requested entry point: %s\n", pszSymbolName );
return NULL;
}
return( pSymbol );
}
#endif /* def _WIN32 */
/* ==================================================================== */
/* Dummy implementation. */
/* ==================================================================== */
#ifndef GOT_GETSYMBOL
/************************************************************************/
/* CPLGetSymbol() */
/* */
/* Dummy implementation. */
/************************************************************************/
void *CPLGetSymbol(const char *pszLibrary, const char *pszEntryPoint)
{
CPLDebug( "CPL",
"CPLGetSymbol(%s,%s) called. Failed as this is stub"
" implementation.", pszLibrary, pszEntryPoint );
return NULL;
}
#endif