sysdeps/pthread/semaphore.h

   1 /* Copyright (C) 2002-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _SEMAPHORE_H
  19 #define _SEMAPHORE_H    1
  20
  21 #include <features.h>
  22 #include <sys/types.h>
  23 #ifdef __USE_XOPEN2K
  24 # include <bits/types/struct_timespec.h>
  25 #endif
  26
  27 /* Get the definition for sem_t.  */
  28 #include <bits/semaphore.h>
  29
  30
  31 __BEGIN_DECLS
  32
  33 /* Initialize semaphore object SEM to VALUE.  If PSHARED then share it
  34    with other processes.  */
  35 extern int sem_init (sem_t *__sem, int __pshared, unsigned int __value)
  36      __THROW;
  37 /* Free resources associated with semaphore object SEM.  */
  38 extern int sem_destroy (sem_t *__sem) __THROW;
  39
  40 /* Open a named semaphore NAME with open flags OFLAG.  */
  41 extern sem_t *sem_open (const char *__name, int __oflag, ...) __THROW;
  42
  43 /* Close descriptor for named semaphore SEM.  */
  44 extern int sem_close (sem_t *__sem) __THROW;
  45
  46 /* Remove named semaphore NAME.  */
  47 extern int sem_unlink (const char *__name) __THROW;
  48
  49 /* Wait for SEM being posted.
  50
  51    This function is a cancellation point and therefore not marked with
  52    __THROW.  */
  53 extern int sem_wait (sem_t *__sem);
  54
  55 #ifdef __USE_XOPEN2K
  56 /* Similar to `sem_wait' but wait only until ABSTIME.
  57
  58    This function is a cancellation point and therefore not marked with
  59    __THROW.  */
  60 extern int sem_timedwait (sem_t *__restrict __sem,
  61                           const struct timespec *__restrict __abstime);
  62 #endif
  63
  64 /* Test whether SEM is posted.  */
  65 extern int sem_trywait (sem_t *__sem) __THROWNL;
  66
  67 /* Post SEM.  */
  68 extern int sem_post (sem_t *__sem) __THROWNL;
  69
  70 /* Get current value of SEM and store it in *SVAL.  */
  71 extern int sem_getvalue (sem_t *__restrict __sem, int *__restrict __sval)
  72      __THROW;
  73
  74
  75 __END_DECLS
  76
  77 #endif  /* semaphore.h */