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Q174403: FIX: Unresolved Externals When Building MFC42 and MFCD42xD

Article: Q174403
Product(s): Microsoft C Compiler
Version(s): winnt:5.0sp1,5.0sp2
Operating System(s): 
Keyword(s): kbDLL kbMFC kbVC500bug kbVS97sp3fix kbGrpDSMFCATL kbNoUpdate
Last Modified: 04-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 Enterprise Edition, version 5.0sp1 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0sp1 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0sp2 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0sp2 
-------------------------------------------------------------------------------

SYMPTOMS
========

When rebuilding Mfc42.dll, Mfcd42d.dll, or Mfcd42ud.dll after installing Visual
Studio 97 Service Pack 1 or Service Pack 2, the "LNK2001: unresolved external
symbol" error message occurs for the following functions:

  AfxThunkSQLDescribeColA
  AfxThunkSQLDriverConnectA
  AfxThunkSQLErrorA
  AfxThunkSQLExecDirectA
  AfxThunkSQLGetCursorNameA
  AfxThunkSQLGetInfoA
  AfxThunkSQLPrepareA
  AfxThunkSQLSetConnectOptionA

CAUSE
=====

The symbols generated for these functions when compiling the file Dbcore.cpp do
not match the function definitions specified for export in Mfc42.def,
Mfcd42d.def, or Mfcd42ud.def.

RESOLUTION
==========

Modify the function definitions in Mfc42.def, mfcd42d.def, or mfcd42ud.def to
match the symbols for the function generated when compiling Dbcore.cpp.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug has been fixed in Visual Studio 97 Service
Pack 3.

For more information, please see the following article in the Microsoft Knowledge
Base:

  Q170365 INFO: Visual Studio 97 Service Packs - What, Where, and Why

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

The difference between the function definitions in Dbcore.cpp and Mfc42.def,
Mfcd42d.def, or Mfcd42ud.def is that the function definitions have an "A"
appended to the function names in Mfc42.def, Mfcd42d.def, or Mfcd42ud.def.

These functions exist in Dbcore.cpp without the "A" appended to the function
name.

Remove the "A" from the function names in question for the .def file you specify
when rebuilding Mfc42.dll, Mfcd42d.dll, or Mfcd42ud.dll.

For example:

Change the following

     ?AfxThunkSQLDescribeColA@@YGFPAXGPAEFPAF2PAK22@Z @ 1507 NONAME

to the following:

     ?AfxThunkSQLDescribeCol@@YGFPAXGPAEFPAF2PAK22@Z @ 1507 NONAME

REFERENCES
==========

See the section "Building the MFC DLL" in TN033 for information on how to
rebuild the MFC DLL.

(c) Microsoft Corporation 1997, All Rights Reserved. Contributions by Isaac
Varon, Microsoft Corporation.
(c) Microsoft Corporation 1997, All Rights Reserved.
Contributions by Isaac Varon, Microsoft Corporation


Additional query words: AfxThunkSQL

======================================================================
Keywords          : kbDLL kbMFC kbVC500bug kbVS97sp3fix kbGrpDSMFCATL kbNoUpdate 
Technology        : kbAudDeveloper kbMFC
Version           : winnt:5.0sp1,5.0sp2
Issue type        : kbbug
Solution Type     : kbfix

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