FIX: Unresolved Externals When Building MFC42 and MFCD42xD

ID: Q174403

The information in this article applies to:

The Microsoft Foundation Classes (MFC), included with:
- Microsoft Visual C++, 32-bit Editions, versions 5.0sp1, 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.

Additional query words: AfxThunkSQL

Keywords : kbMFC kbVC500bug kbVS97sp3fix
Version : WINNT:5.0sp1,5.0sp2
Platform : winnt
Issue type : kbbug