Q271208: BUG: Crash in Mfc42(d).dll During Process Exit on Windows 95, W

Article: Q271208
Product(s): Microsoft C Compiler
Version(s): 6.0
Operating System(s): 
Keyword(s): kbMFC kbVC600bug kbOSWin95 kbOSWin98 kbOSWinME
Last Modified: 23-JUN-2001

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The information in this article applies to:

- Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0, on platform(s):
   - Microsoft Windows Millennium Edition 
   - Microsoft Windows 98 
- Microsoft Visual C++, 32-bit Professional Edition, version 6.0, on platform(s):
   - Microsoft Windows Millennium Edition 
   - Microsoft Windows 98 
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0, on platform(s):
   - Microsoft Windows Millennium Edition 
   - Microsoft Windows 98 
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SYMPTOMS
========

When a process exits, you may experience a crash in the Mfc42.dll or Mfc42d.dll
file on Microsoft Windows 95, Microsoft Windows 98, or Microsoft Windows
Millennium (Me).

CAUSE
=====

The Mfc42(d).dll file assumes it is cleaning up on the main thread and relies on
the handle map that is stored into a thread-local storage value for the main
thread. If the handle map is missing, Microsoft Foundation Class Library (MFC)
may crash.

On a computer that is running Windows 95, Windows 98, or Windows Me, you can run
DLL_PROCESS_DETACH on any thread, rather than the thread that called the
ExitProcess function. (Microsoft Windows NT and Microsoft Windows 2000 exit the
process on the thread that called ExitProcess.)

RESOLUTION
==========

Use the static MFC library and not the shared MFC dynamic-link library (DLL).

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

1. Create a new MFC project and accept all the defaults.

2. Use class wizard to add a new handler for ID_FILE_OPEN in the CWinApp-derived
  class. Edit the code to read as follows:

      void CAssertApp::OnFileOpen()
      {
          CFileDialog dlg(TRUE);
          dlg.DoModal();
          ASSERT(FALSE);
      }

3. In the message map in the Assert.cpp file, remove the line that maps
  ID_FILE_OPEN to the CWinApp::OnFileOpen function.

4. Build the debug configuration.

5. Press F5 (on the Debug menu, and then click Go).

6. In the application, click the toolbar button to open a file.

7. Click Cancel in the Open File dialog box.

  The assertion is hit and a dialog box titled Debug Assertion Failed! is
  displayed.

8. Click Abort.

This is known to crash on Windows 98 Second Edition.

Additional query words:

======================================================================
Keywords          : kbMFC kbVC600bug kbOSWin95 kbOSWin98 kbOSWinME 
Technology        : kbVCsearch kbAudDeveloper kbVC32bitSearch
Version           : :6.0
Issue type        : kbbug

=============================================================================

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