On Thu, Dec 17, 2015 at 10:03 PM, Svante Signell <[email protected]> wrote: > On Thu, 2015-12-17 at 21:05 +0900, Roger Shimizu wrote: >> > For GNU/Hurd the preprocessor directive is __GNU__ >> >> Thanks for your reply! >> I guess like Linux and kFreeBSD, __GLIBC__ is also set in Debian Hurd, right? >> >> BTW. Please CC me when replying. I'd appreciate that! > > No, __GLIBC__ is not set by default for Hurd, only when <features.h> is > included: > touch test.h > <empty> > > gcc -E -dM ./test.h|grep _GNU_ > #define __GNU__ 1 > > gcc -E -dM ./test.h|grep _GLIBC_ > <empty> > > cat test.h > #include <features.h> > > gcc -E -dM ./test.h|grep __GLIBC__ > #define __GLIBC__ 2
Thanks for the detailed way to verify those! I confirmed for __GLIBC__, it's the same situation under GNU/Linux, which default is "No", but turn to "Yes" after include <features.h>. Since basic function like <stdio.h> or <string.h>, etc. also include <features.h>, it's safe for most common application to treat __GLIBC__ as "Yes" for Linux and Hurd. Cheers, Roger
