/****************************************************************************** * $Id: cplgetsymbol.cpp,v 1.16 2006/03/21 20:11:54 fwarmerdam Exp $ * * Project: Common Portability Library * Purpose: Fetch a function pointer from a shared library / DLL. * Author: Frank Warmerdam, warmerdam@pobox.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 1.16 2006/03/21 20:11:54 fwarmerdam * fixup headers a bit * * Revision 1.15 2006/02/19 21:54:34 mloskot * [WINCE] Changes related to Windows CE port of CPL. Most changes are #ifdef wrappers. * * 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 1.16 2006/03/21 20:11:54 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: * * * 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 #if defined(WIN32CE) # include "cpl_win32ce_api.h" #else # include #endif /************************************************************************/ /* 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