[Bug other/53889] New: Gthreads doesn't support destroying recursive mutexes

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53889

             Bug #: 53889
           Summary: Gthreads doesn't support destroying recursive mutexes
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: r...@gcc.gnu.org


There is no __gthread_recursive_mutex_destroy function in the gthreads API.

Using __gthread_mutex_destroy fails to compile on platforms where the mutex
types are different. This means to avoid resource leaks libstdc++ needs to hack
around it with:

    // FIXME: gthreads doesn't define __gthread_recursive_mutex_destroy
    // so we need to obtain a __gthread_mutex_t to destroy
  private:
    template<typename _Mx, typename _Rm>
      static void
      _S_destroy_win32(_Mx* __mx, _Rm const* __rmx)
      {
        __mx->counter = __rmx->counter;
        __mx->sema = __rmx->sema;
        __gthread_mutex_destroy(__mx);
      }

    // matches a gthr-win32.h recursive mutex
    template<typename _Rm>
      static typename __enable_if<(bool)sizeof(&_Rm::sema), void>::__type
      _S_destroy(_Rm* __mx)
      {
        __gthread_mutex_t __tmp;
        _S_destroy_win32(&__tmp, __mx);
      }

    // matches a recursive mutex with a member 'actual'
    template<typename _Rm>
      static typename __enable_if<(bool)sizeof(&_Rm::actual), void>::__type
      _S_destroy(_Rm* __mx)
      { __gthread_mutex_destroy(&__mx->actual); }

    // matches when there's only one mutex type
    template<typename _Rm>
      static typename
      __enable_if<std::__are_same<_Rm, __gthread_mutex_t>::__value,
        void>::__type
      _S_destroy(_Rm* __mx)
      { __gthread_mutex_destroy(__mx); }


Gthreads should define __gthread_recursive_mutex_destroy