https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71013
--- Comment #5 from John David Anglin <danglin at gcc dot gnu.org> --- It seems on gnu systems, _GNU_SOURCE is defined in CPLUSPLUS_CPP_SPEC irrespective of -std=gnu++98. This is in gnu-user.h: /* The GNU C++ standard library requires that these macros be defined. */ #undef CPLUSPLUS_CPP_SPEC #define CPLUSPLUS_CPP_SPEC "-D_GNU_SOURCE %(cpp)" As a result, all C features through to C11 are enabled for c++ on at least Debian unstable. Is this correct? I could do something similar for hpux so the macros get defined.
