Q116026: FIX: ExitInstance() Not Called in _USRDLL DLL

Article: Q116026
Product(s): Microsoft C Compiler
Version(s): winnt:
Operating System(s): 
Keyword(s): kbATL kbDLL kbMFC kbVC kbVC100bug kbVC150bug kbVC200fixkbbuglist kbfixlist
Last Modified: 07-MAY-2001

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The information in this article applies to:

- The Microsoft Foundation Classes (MFC), used with:
   - Microsoft Visual C++ 32-bit Edition, version 1.0 
-------------------------------------------------------------------------------

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 <afxwin.h>

     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          : kbATL kbDLL kbMFC kbVC kbVC100bug kbVC150bug kbVC200fix kbbuglist kbfixlist
Technology        : kbAudDeveloper kbMFC
Version           : winnt:
Issue type        : kbbug
Solution Type     : kbfix

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