http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55007
--- Comment #2 from Earnie <earnie at users dot sourceforge.net> 2012-10-21 17:05:05 UTC --- Sorry, yes -cpp is needed. gcc -cpp -E -dM nul.f | grep -i win Produces an empty result Expected: #define _WIN32 1 #define __WINT_MAX__ 65535 #define __WINT_MIN__ 0 #define __WIN32 1 #define __WINNT 1 #define __WINNT__ 1 #define __WIN32__ 1 #define __SIZEOF_WINT_T__ 2 #define WIN32 1 #define __WINT_TYPE__ short unsigned int #define WINNT 1 $ gcc --version gcc.exe (GCC) 4.7.0 But I stated that in the meta data.