PRB: LNK2005 Errors on New and Delete When Defining _ATL_MIN_CRT

• Microsoft Visual C++, 32-bit Editions, versions 5.0, 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

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

Keywords : kberrmsg kbActiveX kbLinker kbVC500 kbVC600 LinkIss
Version : winnt:5.0,6.0
Platform : winnt
Issue type : kbprb