AudioManagerDaemon/pluginTemplate.h

   1 /*
   2  * pluginTemplate.h
   3  *
   4  *  Created on: Jul 27, 2011
   5  *      Author: christian
   6  */
   7
   8 #ifndef PLUGINTEMPLATE_H_
   9 #define PLUGINTEMPLATE_H_
  10
  11 #include <iostream>
  12 #include <stdio.h>
  13 #include <dirent.h>
  14 #include <dlfcn.h>
  15 #include <libgen.h>
  16 #include <unistd.h>
  17 #include <string>
  18
  19 #include "audioManagerIncludes.h"
  20
  21 template<class T>T* getCreateFunction(std::string libname) {
  22
  23         // cut off directories
  24         char* fileWithPath = const_cast<char*>(libname.c_str());
  25         std::string libFileName = basename(fileWithPath);
  26
  27         // cut off "lib" in front and cut off .so end"
  28         std::string createFunctionName = libFileName.substr(3, libFileName.length() - 6) + "Factory";
  29         DLT_LOG(AudioManager,DLT_LOG_INFO, DLT_STRING("Lib entry point name "),DLT_STRING(createFunctionName.c_str()));
  30
  31         // open library
  32         void *libraryHandle;
  33         dlerror(); // Clear any existing error
  34         libraryHandle = dlopen(libname.c_str(), RTLD_NOW /*LAZY*/);
  35         const char* dlopen_error = dlerror();
  36         if (!libraryHandle || dlopen_error)
  37         {
  38                 DLT_LOG(AudioManager,DLT_LOG_INFO, DLT_STRING("dlopen failed"),DLT_STRING(dlopen_error));
  39                 return 0;
  40         }
  41
  42         // get entry point from shared lib
  43         dlerror(); // Clear any existing error
  44         DLT_LOG(AudioManager,DLT_LOG_INFO, DLT_STRING("loading external function with name"),DLT_STRING(createFunctionName.c_str()));
  45
  46         union
  47         {
  48                 void* voidPointer;
  49                 T* typedPointer;
  50         } functionPointer;
  51
  52         // Note: direct cast is not allowed by ISO C++. e.g.
  53         // T* createFunction = reinterpret_cast<T*>(dlsym(libraryHandle, createFunctionName.c_str()));
  54         // compiler warning: "forbids casting between pointer-to-function and pointer-to-object"
  55
  56         functionPointer.voidPointer = dlsym(libraryHandle, createFunctionName.c_str());
  57         T* createFunction = functionPointer.typedPointer;
  58
  59         const char* dlsym_error = dlerror();
  60         if (!createFunction || dlsym_error)
  61         {
  62                 DLT_LOG(AudioManager,DLT_LOG_INFO, DLT_STRING("Failed to load shared lib entry point"),DLT_STRING(dlsym_error));
  63         }
  64
  65         return createFunction;
  66 }
  67
  68
  69 #endif /* PLUGINTEMPLATE_H_ */