error LNK2005: _DllMain@12 already defined in MSVCRT.lib

Question

I am getting this linker error.

mfcs80.lib(dllmodul.obj) : error LNK2005: _DllMain@12 already defined in MSVCRT.lib(dllmain.obj)

Answer 1

Just #undef the _USRDLL before including afx.h, or even better, edit your project configuration and remove the macro.

This is the usual configuration for a MFC extension DLL: Build Settings for an MFC DLL