include/bits/semaphore.h

   1 /* Generic POSIX semaphore type layout
   2    Copyright (C) 1995-2021 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 #ifndef _SEMAPHORE_H
  20 # error "Never use <bits/semaphore.h> directly; include <semaphore.h> instead."
  21 #endif
  22
  23 #include <bits/wordsize.h>
  24
  25 #if __WORDSIZE == 64
  26 # define __SIZEOF_SEM_T 32
  27 #else
  28 # define __SIZEOF_SEM_T 16
  29 #endif
  30
  31 /* Value returned if `sem_open' failed.  */
  32 #define SEM_FAILED      ((sem_t *) 0)
  33
  34
  35 typedef union
  36 {
  37   char __size[__SIZEOF_SEM_T];
  38   long int __align;
  39 } sem_t;