Re: [gentoo-musl] [GSoC] _GNU_SOURCE in C++

[Lei Zhang]

2016-06-17 20:44 GMT+08:00 Lei Zhang <zhanglei.april@×××××.com>:
> After putting about eight "#define _GNU_SOURCE"s in various *.cpp
> files, it seems to work now :)

I was wrong; it doesn't work... I still can't figure out a good solution :(

Take glibc's strtoll_l for example: it's hidden by _GNU_SOURCE in
stdlib.h and used exclusively by libc++'s header <locale>; but
defining _GNU_SOURCE in <locale> could be too late, since stdlib.h
might be included prior to <locale>.

Though glibc's stdlib.h is only explicitly included in <cstdlib>,
defining _GNU_SOURCE in <cstdlib> doesn't work either. It turns out
strtoll_l (and others) is not directly protected by _GNU_SOURCE, but
by __USE_GNU, which is in turn defined in features.h according to
_GNU_SOURCE. That means "#define _GNU_SOURCE" must appear before the
inclusion of features.h, and it's not very clear where "#undef
_GNU_SOURCE" should be put.

Any suggestions?


Lei