Emil Velikov wrote:
> On 3 February 2015 at 02:53, Emil Velikov <emil.l.veli...@gmail.com> wrote:
> > Hi Felix,
> >
Thanks for the review.
> > On 2 February 2015 at 19:04, Felix Janda <felix.ja...@posteo.de> wrote:
> >> Previously PTHREAD_MUTEX_RECURSIVE_NP had been used on linux for
> >> compatibility with old glibc. Since mesa defines __GNU_SOURCE__
> >> on linux PTHREAD_MUTEX_RECURSIVE is also available since at least
> >> 1998. So we can unconditionally use the portable version
> >> PTHREAD_MUTEX_RECURSIVE.
> >> ---
> >> Previous patch didn't work as intended since on glibc these are
> >> part of an enum and not defines.
> >>
> > From a quick look at {e,}glibc sources [1]
> >
> > PTHREAD_MUTEX_RECURSIVE_NP,
> > ...
> > #if defined __USE_UNIX98 || defined __USE_XOPEN2K8
> > ...
> > PTHREAD_MUTEX_RECURSIVE = PTHREAD_MUTEX_RECURSIVE_NP,
> > ...
> >
> > Which does not seem to have relation with _GNU_SOURCE_ as the commit
> > mentions. Note I don't even pretend to know the convoluted web of
> > macros, so I could be a bit off :-)
> >
_GNU_SOURCE basically stands for "enable everything". I've checked that
for glibc 2.1 it defined _XOPEN_SOURCE=500 which in turn defines
__USE_UNIX98.
> Upon closer look things could be fine, as
>
> linux/gnu: _GNU_SOURCE sets _POSIX_C_SOURCE 200809L.
> With the latter of which guarding the __USE_XOPEN2K8 definition.
>
> cygwin: (hmm does it even set __linux*) we set _XOPEN_SOURCE=700.
> Which is the guard for __USE_XOPEN2K8.
http://nadeausoftware.com/articles/2012/01/c_c_tip_how_use_compiler_predefined_macros_detect_operating_system
seems to indicate that it doesn't. I don't think that anything but
glibc has PTHREAD_MUTEX_RECURSIVE_NP.
> If one wants to be extra careful we can change
> #if defined(__linux__) || defined(__linux)
> to check for the said old versions of glibc, but I believe we should be safe.
#if defined(__GLIBC__) is fine, too. Unless you care about hurd:
https://bugzilla.gnome.org/show_bug.cgi?id=377066
Something along this line is necessary (and sufficient) to compile
mesa unmodified with musl libc.
Felix
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