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Filename : semaphore.h
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/* Copyright (C) 2002-2018 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#ifndef _SEMAPHORE_H
#define _SEMAPHORE_H	1

#include <features.h>
#include <sys/types.h>
#ifdef __USE_XOPEN2K
# include <bits/types/struct_timespec.h>
#endif

/* Get the definition for sem_t.  */
#include <bits/semaphore.h>


__BEGIN_DECLS

/* Initialize semaphore object SEM to VALUE.  If PSHARED then share it
   with other processes.  */
extern int sem_init (sem_t *__sem, int __pshared, unsigned int __value)
     __THROW;
/* Free resources associated with semaphore object SEM.  */
extern int sem_destroy (sem_t *__sem) __THROW;

/* Open a named semaphore NAME with open flags OFLAG.  */
extern sem_t *sem_open (const char *__name, int __oflag, ...) __THROW;

/* Close descriptor for named semaphore SEM.  */
extern int sem_close (sem_t *__sem) __THROW;

/* Remove named semaphore NAME.  */
extern int sem_unlink (const char *__name) __THROW;

/* Wait for SEM being posted.

   This function is a cancellation point and therefore not marked with
   __THROW.  */
extern int sem_wait (sem_t *__sem);

#ifdef __USE_XOPEN2K
/* Similar to `sem_wait' but wait only until ABSTIME.

   This function is a cancellation point and therefore not marked with
   __THROW.  */
extern int sem_timedwait (sem_t *__restrict __sem,
			  const struct timespec *__restrict __abstime);
#endif

/* Test whether SEM is posted.  */
extern int sem_trywait (sem_t *__sem) __THROWNL;

/* Post SEM.  */
extern int sem_post (sem_t *__sem) __THROWNL;

/* Get current value of SEM and store it in *SVAL.  */
extern int sem_getvalue (sem_t *__restrict __sem, int *__restrict __sval)
     __THROW;


__END_DECLS

#endif	/* semaphore.h */