KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q184235: PRB: LNK2005 Errors on New and Delete When Defining _ATL_MIN_CRT

Article: Q184235
Product(s): Microsoft C Compiler
Version(s): 5.0,6.0
Operating System(s): 
Keyword(s): kberrmsg kbActiveX kbLinker kbVC500 kbVC600
Last Modified: 11-JUN-2002

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Visual C++, 32-bit Enterprise Edition, versions 5.0, 6.0 
- Microsoft Visual C++, 32-bit Professional Edition, versions 5.0, 6.0 
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

When you compile an Active Template Library (ATL) executable (.exe) project in
Developer Studio, the _ATL_MIN_CRT preprocessor symbol allows you to use some
standard C library functions without having to link in the C run-time library
(CRT) startup code. If _ATL_MIN_CRT is defined when you build an ATL executable
with Microsoft Foundation Classes (MFC) support, the linker returns the
following linker errors:

  nafxcw.lib(afxmem.obj) : error LNK2005: "void * _cdecl operator new(unsigned
  int)" (??2@YAPAXI@Z) already defined in Stdafx.obj

  nafxcw.lib(afxmem.obj) : error LNK2005: "void __cdecl operator delete(void
  *)" (??3@YAXPAX@Z) already defined in StdAfx.obj

CAUSE
=====

Some C run-time library functions require that you provide the CRT startup code.
Because both the C run-time and MFC libraries contain definitions for the new
and delete operators, there is a conflict for the linker.

RESOLUTION
==========

Remove the _ATL_MIN_CRT preprocessor definition and rebuild the project. To do
this, click Settings on the Project menu. On the C/C++ tab, select the
Preprocessor category, and remove the _ATL_MIN_CRT definition.

STATUS
======

This behavior is by design.

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

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

1. Create an ATL COM AppWizard application. On the File menu, click New, and
  select ATL COM AppWizard as the project type.

2. Use the information in the following Microsoft Knowledge Base article to add
  MFC support to your ATL project:

  Q173974 HOWTO: Add MFC Support to an ATL Project

3. Add _ATL_MIN_CRT to your preprocessor definitions using the preprocessor
  settings described in the RESOLUTION section of this article.

4. On the Build menu, click Set Active Configuration, and choose the Win32
  Release MinSize configuration.

5. Build the project. You should see both LNK2005 errors in the build output
  window.

REFERENCES
==========

For additional information, please see the following articles in the Microsoft
Knowledge Base:

  Q173974 HOWTO: Add MFC Support to an ATL Project

(c) Microsoft Corporation 1998, All Rights Reserved. Contributions by Mark Hagen,
Microsoft Corporation.


Additional query words: ActiveX Foundation Classes C++ CPP CXX

======================================================================
Keywords          : kberrmsg kbActiveX kbLinker kbVC500 kbVC600 
Technology        : kbVCsearch kbAudDeveloper kbVC500 kbVC600 kbVC32bitSearch kbVC500Search
Version           : :5.0,6.0
Issue type        : kbprb

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.