M:\Development\x64\test>g++ -dumpversion && g++ test.cpp -mwindows -o test
4.7.1
m:/development/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/4.7.1/../../../../x86_64-w64-mingw32/lib/../lib/libmingw32.a(lib64_libmingw32_a-crt0_c.o): In function
`main':
/home/ruben/mingw-w64/toolchain/src/mingw-w64/tags/v2.0.3/mingw-w64-crt/crt/crt0_c.c:18: undefined reference to `WinMain'
collect2.exe: error: ld returned 1 exit status

M:\Development\x64\test>