Microsoft KB Archive/116026

= FIX: ExitInstance Not Called in _USRDLL DLL =

Article ID: 116026

Article Last Modified on 11/21/2006

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APPLIES TO


 * Microsoft Foundation Class Library 4.2

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This article was previously published under Q116026



SYMPTOMS
CWinApp::ExitInstance never gets called for the CWinApp object in a _USRDLL built with the Microsoft Foundation Classes (MFC) for Windows NT, version 2.1.



CAUSE
The DLLMain function for a _USRDLL is provided by MFC. This function can be found in the MFC source directory (MSVC\MFC\SRC by default) in the file WINMAIN.CPP. Unlike a Windows 3.1 DLL, which has both an initialization and a termination function, a Windows NT DLL calls one function, DLLMain, for both purposes. The DLLMain function supplied by MFC has no call to ExitInstance when DLL_PROCESS_DETACH is received.



RESOLUTION
Provide your own DLLMain function in your _USRDLL project by copying the current DLLMain implementation into a new .CPP module and add the new .CPP file to your project. Modify the new DLLMain to add the calls to ExitInstance where necessary. The new module would look like this: //   // FILE - DLLMAIN.CPP //

#include 

extern "C" int APIENTRY DllMain(HINSTANCE hInstance, DWORD dwReason, LPVOID lpReserved) {       if (dwReason == DLL_PROCESS_ATTACH) {            // Initialize DLL's instance(/module) not the app's             if (!AfxWinInit(hInstance, NULL, "", 0)) {                 AfxWinTerm; return 0;      // Init Failed }

// initialize the single instance DLL if (!AfxGetApp->InitInstance) {             if(AfxGetApp!=NULL) AfxGetApp->ExitInstance; AfxWinTerm; return 0;      // Init Failed }       }        else if (dwReason == DLL_PROCESS_DETACH) {          if(AfxGetApp!=NULL) AfxGetApp->ExitInstance;

// Terminate the library before destructors are called AfxWinTerm; }

return 1;  // ok   }

//   // EOF - DLLMAIN.CPP //



STATUS
Microsoft has confirmed this to be a bug in the products listed at the beginning of this article. This problem was corrected in MFC version 3.0, included with Microsoft Visual C++ 32-bit Edition, version 2.0.

Additional query words: 1.00 2.00 2.10

Keywords: kbbug kbdll kbfix kbvc200fix KB116026

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