sysdeps/pthread/mtx_init.c

   1 /* C11 threads mutex initialization implementation.
   2    Copyright (C) 2018-2023 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 <stdalign.h>
  20 #include <shlib-compat.h>
  21
  22 #include "thrd_priv.h"
  23
  24 int
  25 __mtx_init (mtx_t *mutex, int type)
  26 {
  27   _Static_assert (sizeof (mtx_t) == sizeof (pthread_mutex_t),
  28                   "sizeof (mtx_t) != sizeof (pthread_mutex_t)");
  29   _Static_assert (alignof (mtx_t) == alignof (pthread_mutex_t),
  30                   "alignof (mtx_t) != alignof (pthread_mutex_t)");
  31
  32   pthread_mutexattr_t attr;
  33
  34   __pthread_mutexattr_init (&attr);
  35
  36   /* Another possible solution would be to set the flags directly in
  37      mutex object. */
  38   switch (type)
  39   {
  40     case mtx_plain | mtx_recursive:
  41     case mtx_timed | mtx_recursive:
  42       __pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);
  43       break;
  44     case mtx_plain:
  45     case mtx_timed: /* No difference between both in standard */
  46     default:
  47       __pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_NORMAL);
  48       break;
  49   }
  50
  51   int err_code = __pthread_mutex_init ((pthread_mutex_t *) mutex, &attr);
  52   /* pthread_mutexattr_destroy implementation is a noop.  */
  53   return thrd_err_map (err_code);
  54 }
  55 #if PTHREAD_IN_LIBC
  56 versioned_symbol (libc, __mtx_init, mtx_init, GLIBC_2_34);
  57 # if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_28, GLIBC_2_34)
  58 compat_symbol (libpthread, __mtx_init, mtx_init, GLIBC_2_28);
  59 # endif
  60 #else /* !PTHREAD_IN_LIBC */
  61 strong_alias (__mtx_init, mtx_init)
  62 #endif