nptl/pthread_mutex_getprioceiling.c

   1 /* Get current priority ceiling of pthread_mutex_t.
   2    Copyright (C) 2006-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <pthreadP.h>
  21 #include <shlib-compat.h>
  22
  23 int
  24 __pthread_mutex_getprioceiling (const pthread_mutex_t *mutex, int *prioceiling)
  25 {
  26   /* See concurrency notes regarding __kind in struct __pthread_mutex_s
  27      in sysdeps/nptl/bits/thread-shared-types.h.  */
  28   if (__builtin_expect ((atomic_load_relaxed (&(mutex->__data.__kind))
  29                          & PTHREAD_MUTEX_PRIO_PROTECT_NP) == 0, 0))
  30     return EINVAL;
  31
  32   *prioceiling = (mutex->__data.__lock & PTHREAD_MUTEX_PRIO_CEILING_MASK)
  33                  >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
  34
  35   return 0;
  36 }
  37 versioned_symbol (libc, __pthread_mutex_getprioceiling,
  38                   pthread_mutex_getprioceiling, GLIBC_2_34);
  39
  40 #if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_4, GLIBC_2_34)
  41 compat_symbol (libpthread, __pthread_mutex_getprioceiling,
  42                pthread_mutex_getprioceiling, GLIBC_2_4);
  43 #endif