The implementation doesn't seem to be correct. Could anybody versed in this look into it? version(Windows) { private extern __gshared fenv_t _FE_DFL_ENV; fenv_t* FE_DFL_ENV = &_FE_DFL_ENV; } There's no such symbol in the libcmt and it fails to link. http://sourceforge.net/p/mingw/mingw-org-wsl/ci/master/tree/include/fenv.h#l87