config/linux/sem.h

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/* Copyright (C) 2005, 2009 Free Software Foundation, Inc.
   Contributed by Richard Henderson <rth@redhat.com>.

   This file is part of the GNU OpenMP Library (libgomp).

   Libgomp is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3, or (at your option)
   any later version.

   Libgomp 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 General Public License for
   more details.

   Under Section 7 of GPL version 3, you are granted additional
   permissions described in the GCC Runtime Library Exception, version
   3.1, as published by the Free Software Foundation.

   You should have received a copy of the GNU General Public License and
   a copy of the GCC Runtime Library Exception along with this program;
   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
   <http://www.gnu.org/licenses/>.  */

/* This is a Linux specific implementation of a semaphore synchronization
   mechanism for libgomp.  This type is private to the library.  This 
   implementation uses atomic instructions and the futex syscall.  */

#ifndef GOMP_SEM_H
#define GOMP_SEM_H 1

typedef int gomp_sem_t;

static inline void gomp_sem_init (gomp_sem_t *sem, int value)
{
  *sem = value;
}

extern void gomp_sem_wait_slow (gomp_sem_t *);
static inline void gomp_sem_wait (gomp_sem_t *sem)
{
  if (!__sync_bool_compare_and_swap (sem, 1, 0))
    gomp_sem_wait_slow (sem);
}

extern void gomp_sem_post_slow (gomp_sem_t *);
static inline void gomp_sem_post (gomp_sem_t *sem)
{
  if (!__sync_bool_compare_and_swap (sem, 0, 1))
    gomp_sem_post_slow (sem);
}

static inline void gomp_sem_destroy (gomp_sem_t *sem)
{
}

#endif /* GOMP_SEM_H */

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