Microsoft KB Archive/168003

= FIX: Function Prototypes in comutil.h Missing Calling Convention =

Article ID: 168003

Article Last Modified on 11/21/2003

-

APPLIES TO


 * Microsoft Visual C++ 5.0 Enterprise Edition
 * Microsoft Visual C++ 5.0 Professional Edition

-



This article was previously published under Q168003



SYMPTOMS
Unresolved external errors may occur when you compile with a default calling convention of __fastcall (/Gr) or __stdcall (/Gz) and call ConvertStringToBSTR or ConvertBSTRToString.



CAUSE
The prototypes are missing the __cdecl calling convention, which is the calling convention of these functions in comsupp.lib.



RESOLUTION
Build with __cdecl as the default calling convention. Do not build with __fastcall or __stdcall as the default calling convention.



STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug has been corrected in Visual Studio 97 Service Pack 1.

For additional information about the Visual Studio 97 Service Pack 1, please see the following article in the Microsoft Knowledge Base:

170365 INFO: Visual Studio 97 Service Packs - What, Where, and Why



Sample Code
//compile options needed: /Gr or /Gz #include   int main {      char sz[]="hello"; _bstr_t b;      b = _com_util::ConvertStringToBSTR(sz); char * p = _com_util::ConvertBSTRToString(b); return 1; } The following linker errors occur when you compile this sample code:

  error LNK2001: unresolved external symbol "char * __fastcall   _com_util::ConvertBSTRToString(unsigned short *)" (?ConvertBSTRToString@_com_util@@YIPADPAG@Z)

  error LNK2001: unresolved external symbol "unsigned short * __fastcall   _com_util::ConvertStringToBS   TR(char const *)" (?ConvertStringToBSTR@_com_util@@YIPAGPBD@Z)

Additional query words: LNK2001

Keywords: kbbug kbfix kbvs97sp1fix kbcode KB168003

-

[mailto:TECHNET@MICROSOFT.COM Send feedback to Microsoft]

© Microsoft Corporation. All rights reserved.