sem.h revision 169695 
1/* Copyright (C) 2005 Free Software Foundation, Inc.
2   Contributed by Richard Henderson <rth@redhat.com>.
3
4   This file is part of the GNU OpenMP Library (libgomp).
5
6   Libgomp is free software; you can redistribute it and/or modify it
7   under the terms of the GNU Lesser General Public License as published by
8   the Free Software Foundation; either version 2.1 of the License, or
9   (at your option) any later version.
10
11   Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
12   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
13   FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for
14   more details.
15
16   You should have received a copy of the GNU Lesser General Public License
17   along with libgomp; see the file COPYING.LIB.  If not, write to the
18   Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
19   MA 02110-1301, USA.  */
20
21/* As a special exception, if you link this library with other files, some
22   of which are compiled with GCC, to produce an executable, this library
23   does not by itself cause the resulting executable to be covered by the
24   GNU General Public License.  This exception does not however invalidate
25   any other reasons why the executable file might be covered by the GNU
26   General Public License.  */
27
28/* This is a Linux specific implementation of a semaphore synchronization
29   mechanism for libgomp.  This type is private to the library.  This
30   implementation uses atomic instructions and the futex syscall.  */
31
32#ifndef GOMP_SEM_H
33#define GOMP_SEM_H 1
34
35typedef int gomp_sem_t;
36
37static inline void gomp_sem_init (gomp_sem_t *sem, int value)
38{
39  *sem = value;
40}
41
42extern void gomp_sem_wait_slow (gomp_sem_t *);
43static inline void gomp_sem_wait (gomp_sem_t *sem)
44{
45  if (!__sync_bool_compare_and_swap (sem, 1, 0))
46    gomp_sem_wait_slow (sem);
47}
48
49extern void gomp_sem_post_slow (gomp_sem_t *);
50static inline void gomp_sem_post (gomp_sem_t *sem)
51{
52  if (!__sync_bool_compare_and_swap (sem, 0, 1))
53    gomp_sem_post_slow (sem);
54}
55
56static inline void gomp_sem_destroy (gomp_sem_t *sem)
57{
58}
59
60#endif /* GOMP_SEM_H */
61