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Q217772: PRB: CAsyncMonikerFile::Open() Fails in Visual C++ 5.0 MFC Apps

Article: Q217772
Product(s): Microsoft C Compiler
Version(s): 6.0
Operating System(s): 
Keyword(s): kbIE400 kbInternet kbMFC kbVC500 kbVC600bug kbIE302 kbBug kbGrpDSMFCATL kbNoUpdate kbIS
Last Modified: 17-MAY-2002

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The information in this article applies to:

- The Microsoft Foundation Classes (MFC), included with:
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
- Microsoft Windows Internet Services (WinInet) 
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SYMPTOMS
========

After installing a Visual C++ 6.0 application that uses MFC, the Mfc42.dll that
was shipped with Visual C++ 6.0 may be installed. This may cause problems for
existing applications that were developed using MFC from Visual C++ 5.0 and that
used the CAsyncMonikerFile class. In particular, a call to
CAsyncMonikerFile::Open() will return an the following error:

  An unknown error occurred while accessing an unknown file

This error occurs on machines that have Internet Explorer 3.02 or earlier
installed.

CAUSE
=====

This problem occurs because of a bug in Visual C++ 6.0's implementation of the
CAsyncMonikerFile MFC class.

RESOLUTION
==========

Use the following steps to work around this problem:

1. Install Internet Explorer 4.0 or higher.

2. Place the Mfc42.dll from the Visual C++ 5.0 version in the same directory as
  the EXE or DLL. This may not be an option if you depend Mfc42.dll being in
  the system directory. For example, an OCX that downloads over the Internet
  would use the version of MFC in the windows system directory.

3. Link to MFC statically for any application developed with Visual C++ 5.0 and
  using CAsyncMonikerFile.

  NOTE: This method does not work for an OCX developed with Visual C++ 5.0
  because you cannot link statically to MFC when developing an OCX in Visual
  C++ 5.0.

Additional query words: Backward compatible bug MFC42.DLL port

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Keywords          : kbIE400 kbInternet kbMFC kbVC500 kbVC600bug kbIE302 kbBug kbGrpDSMFCATL kbNoUpdate kbISS 
Technology        : kbAudDeveloper kbMFC
Version           : :6.0
Issue type        : kbprb

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