error LNK2005: new and delete already defined in LIBCMTD.lib(new.obj)

Question

Hi All,

I have a Visual studio 2005 solution that has two projects. One is a static library and the other is a executable used to test the features in the static library. The static library uses MFC. I got the following errors when I built the solution.

uafxcwd.lib(afxmem.obj) : error LNK2005: "void * __cdecl operator new(unsigned int)" (??2@YAPAXI@Z) already defined in LIBCMTD.lib(new.obj)
uafxcwd.lib(afxmem.obj) : error LNK2005: "void __cdecl operator delete(void *)" (??    3@YAXPAX@Z) already defined in LIBCMTD.lib(dbgdel.obj)
uafxcwd.lib(afxmem.obj) : error LNK2005: "void * __cdecl operator new[](unsigned int)" (??_U@YAPAXI@Z) already defined in libcpmtd.lib(newaop.obj)
uafxcwd.lib(afxmem.obj) : error LNK2005: "void __cdecl operator delete[](void *)" (??_V@YAXPAX@Z) already defined in LIBCMTD.lib(delete2.obj)

I do not know how to overcome this. Can some one please explain why this error is occuring. Any explanation that gives an overview of .lib files linkage will be highly appreciated.

Answer 1

Check the manifest file of both projects, make sure that they are linking the same version of the standard library. Most likely they are not, check the properties->code generation->standard library linking.

Answer 2

Make sure the C++ runtime library that you are linking with is the same on your static library as well as your executable. Check your project properties C/C++->Code generation->runtime library settings.

Answer 3

If the other (non static library) project is a CRT project, check out this link:

http://support.microsoft.com/kb/148652

Answer 4

First, libcmtd.lib is for a debug version and libcmt.lib is for production. Double-check that you're not including both. One place to check is the "Command Line" section of the Configuration Properties/Linker project properties.

If you go to the properties for the project, and open up the Configuration Properties/Linker/Input section, you can "Ingore Specific Library"...try listing libcmtd.lib in that field.

Answer 5

The CRT libraries use weak external linkage for the new, delete, and DllMain functions. The MFC libraries also contain new, delete, and DllMain functions. These functions require the MFC libraries to be linked before the CRT library is linked. http://support.microsoft.com/kb/148652

Solution based on VS2005

go to project>properties>configuration properties>linker>input

add to "Additional dependency" -> Nafxcwd.lib Libcmtd.lib

add to "ignore specific library" -> Nafxcwd.lib;Libcmtd.lib

order of libraries is important( Nafxcwd.lib;Libcmtd.lib).