[Bug libstdc++/51008] New: GTHR - extend interface with __gthread_recursive_mutex_destroy

["andvgal at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51008

             Bug #: 51008
           Summary: GTHR - extend interface with
                    __gthread_recursive_mutex_destroy
    Classification: Unclassified
           Product: gcc
           Version: 4.6.2
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: andvgal@gmail.com


This is not a direct libstdc++ bug, but an interface issue of gthreads. I
haven't found a similar bug report except for #46455.

The issue appears because in libstdc++-v3/include/ext/concurrence.h in d-tor of
__recursive_mutex class, when a custom GTHR implementation is used (We have to
provide one for a legacy non-POSIX OS).
According to SVN, the problem still exists in branch 4.6 and trunk.


I can propose two solutions:
1. Add __gthread_recursive_mutex_destroy and get rid of _S_destroy template
hacks.

2. Add a new macro __GTHREAD_RECURSIVE_MUTEX_DESTROY_FUNCTION. If the macro is
defined by GTHR implementation then __mutex d-tor shall call it instead of
_S_destroy hacks.
It shall be also a good solution for Win32 and other custom destructors.


IMO, the first one is the most correct. The second is suitable to maintain
backward compatibility and is the least risky.
I can provide a patch for the second approach, if needed.