/* Get current priority ceiling of pthread_mutex_t.

   Copyright (C) 2006-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Jakub Jelinek <jakub@redhat.com>, 2006.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <errno.h>

#include <pthreadP.h>

int

pthread_mutex_getprioceiling (const pthread_mutex_t *mutex, int *prioceiling)

{

  /* See concurrency notes regarding __kind in struct __pthread_mutex_s

     in sysdeps/nptl/bits/thread-shared-types.h.  */

  if (__builtin_expect ((atomic_load_relaxed (&(mutex->__data.__kind))

			 & PTHREAD_MUTEX_PRIO_PROTECT_NP) == 0, 0))

    return EINVAL;

  *prioceiling = (mutex->__data.__lock & PTHREAD_MUTEX_PRIO_CEILING_MASK)

		 >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT;

  return 0;

}