[Bug libstdc++/51296] Several 30_threads tests FAIL on Tru64 UNIX

[ro at CeBiTec dot Uni-Bielefeld.DE]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51296

--- Comment #26 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> 2012-01-16 18:58:20 UTC ---
> --- Comment #25 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-01-13 10:37:52 UTC ---
> Nice digging.  POSIX does say the INIT macro is for use when the mutex is
> statically-allocated:
>
> "In cases where default mutex attributes are appropriate, the macro
> PTHREAD_MUTEX_INITIALIZER can be used to initialize mutexes that are statically
> allocated."
>
>
> For most platforms it works fine for automatic variables and in C++ for member
> variables too.
>
> Maybe something scans the BSS segment at startup to find mutexes?!  In any
> case, it looks as though we should definitely use the init function instead of
> the macro on Tru64.

Unfortunately, while my test to do so fixes the 30_threads failures, it
introduced tons of failures elsewhere (both libstdc++ and others).  I
don't fully understand what's happening there, but perhaps we need a fix
in libstdc++ instead, especially given that the use of
PTHREAD_MUTEX_INITIALIZER at hand isn't standard-conforming.

    Rainer