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