Implementation of Dll calling main program (client, external program, host) function

      After referring to a large number of URLs (now listed below), I only found some sporadic code snippets. As a novice like me, it is really difficult to easily write the specific implementation code.

          http://topic.csdn.net/t/20060719/14/4890502.html

          http://tech.techweb.com.cn/archiver/tid-224521.html

          http://group.gimoo.net/review/8312

      After a day of tossing, I finally implemented a simple example. In order to record my own results, it also provides an intuitive reference for beginners like me and saves learning time. The example code is now attached. Note: My programming platform is: Visual Studio2008 express

//dll.h #ifndef _DLL_H #define _DLL_H #endif #ifdef DLL_API #else #define DLL_API extern "C" _declspec(dllimport) #endif typedef void ( *PFN_MYCALLBACK)(); DLL_API void _SetCallbackFun(PFN_MYCALLBACK pCallbackFun); 

dll.cpp

#define DLL_API extern "C" _declspec(dllexport) #include "dll.h" void _SetCallbackFun(PFN_MYCALLBACK pCallbackFun) { if (0 != pCallbackFun) { pCallbackFun(); } }

 

The client program (main program) is a dialog-based MFC application, in which a global function is customized for the DLL to call. When the ok button is clicked, the dll is loaded to implement the call.

void retunfun() { AfxMessageBox(_T("dllTest"));//测试全局函数 }

#includ "dll.h" //包含dll头文件 void CDLLTestDlg::OnOK() { typedef void ( *ADDPROC)(PFN_MYCALLBACK);//定义导出函数的指针类型 HINSTANCE hModDll; hModDll = ::LoadLibrary(_T("dll.dll")); if (NULL == hModDll) return; ADDPROC pMainFunc = (ADDPROC)::GetProcAddress(hModDll, "_SetCallbackFun"); if(NULL != pMainFunc) pMainFunc((PFN_MYCALLBACK)retunfun); //CDialog::OnOK(); }

Follow the above steps to add and it will run. Note that there is a calling convention issue. This test example defaults to the Visual C++ compiler calling convention.