1/* Get current priority ceiling of pthread_mutex_t.
2 Copyright (C) 2006-2020 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Jakub Jelinek <jakub@redhat.com>, 2006.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#include <errno.h>
21#include <pthreadP.h>
22
23
24int
25pthread_mutex_getprioceiling (const pthread_mutex_t *mutex, int *prioceiling)
26{
27 /* See concurrency notes regarding __kind in struct __pthread_mutex_s
28 in sysdeps/nptl/bits/thread-shared-types.h. */
29 if (__builtin_expect ((atomic_load_relaxed (&(mutex->__data.__kind))
30 & PTHREAD_MUTEX_PRIO_PROTECT_NP) == 0, 0))
31 return EINVAL;
32
33 *prioceiling = (mutex->__data.__lock & PTHREAD_MUTEX_PRIO_CEILING_MASK)
34 >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
35
36 return 0;
37}
38