nptl/semaphore.h

   1 /* Copyright (C) 2002-2014 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 # define __need_timespec
  25 # include <time.h>
  26 #endif
  27
  28 /* Get the definition for sem_t.  */
  29 #include <bits/semaphore.h>
  30
  31
  32 __BEGIN_DECLS
  33
  34 /* Initialize semaphore object SEM to VALUE.  If PSHARED then share it
  35    with other processes.  */
  36 extern int sem_init (sem_t *__sem, int __pshared, unsigned int __value)
  37      __THROW;
  38 /* Free resources associated with semaphore object SEM.  */
  39 extern int sem_destroy (sem_t *__sem) __THROW;
  40
  41 /* Open a named semaphore NAME with open flags OFLAG.  */
  42 extern sem_t *sem_open (const char *__name, int __oflag, ...) __THROW;
  43
  44 /* Close descriptor for named semaphore SEM.  */
  45 extern int sem_close (sem_t *__sem) __THROW;
  46
  47 /* Remove named semaphore NAME.  */
  48 extern int sem_unlink (const char *__name) __THROW;
  49
  50 /* Wait for SEM being posted.
  51
  52    This function is a cancellation point and therefore not marked with
  53    __THROW.  */
  54 extern int sem_wait (sem_t *__sem);
  55
  56 #ifdef __USE_XOPEN2K
  57 /* Similar to `sem_wait' but wait only until ABSTIME.
  58
  59    This function is a cancellation point and therefore not marked with
  60    __THROW.  */
  61 extern int sem_timedwait (sem_t *__restrict __sem,
  62                           const struct timespec *__restrict __abstime);
  63 #endif
  64
  65 /* Test whether SEM is posted.  */
  66 extern int sem_trywait (sem_t *__sem) __THROWNL;
  67
  68 /* Post SEM.  */
  69 extern int sem_post (sem_t *__sem) __THROWNL;
  70
  71 /* Get current value of SEM and store it in *SVAL.  */
  72 extern int sem_getvalue (sem_t *__restrict __sem, int *__restrict __sval)
  73      __THROW;
  74
  75
  76 __END_DECLS
  77
  78 #endif  /* semaphore.h */