1 /* Linuxthreads - a simple clone()-based implementation of Posix */
2 /* threads for Linux. */
3 /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */
5 /* This program is free software; you can redistribute it and/or */
6 /* modify it under the terms of the GNU Library General Public License */
7 /* as published by the Free Software Foundation; either version 2 */
8 /* of the License, or (at your option) any later version. */
10 /* This program is distributed in the hope that it will be useful, */
11 /* but WITHOUT ANY WARRANTY; without even the implied warranty of */
12 /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
13 /* GNU Library General Public License for more details. */
16 #define _SEMAPHORE_H 1
19 #include <sys/types.h>
22 # define __need_timespec
26 #ifndef _PTHREAD_DESCR_DEFINED
27 /* Thread descriptors. Needed for `sem_t' definition. */
28 typedef struct _pthread_descr_struct *_pthread_descr;
29 # define _PTHREAD_DESCR_DEFINED
32 /* System specific semaphore definition. */
35 struct _pthread_fastlock __sem_lock;
37 _pthread_descr __sem_waiting;
42 /* Value returned if `sem_open' failed. */
43 #define SEM_FAILED ((sem_t *) 0)
45 /* Maximum value the semaphore can have. */
47 #define SEM_VALUE_MAX (2147483647)
53 /* Initialize semaphore object SEM to VALUE. If PSHARED then share it
54 with other processes. */
55 extern int sem_init (sem_t *__sem, int __pshared, unsigned int __value) __THROW;
57 /* Free resources associated with semaphore object SEM. */
58 extern int sem_destroy (sem_t *__sem) __THROW;
60 /* Open a named semaphore NAME with open flags OFLAG. */
61 extern sem_t *sem_open (const char *__name, int __oflag, ...) __THROW;
63 /* Close descriptor for named semaphore SEM. */
64 extern int sem_close (sem_t *__sem) __THROW;
66 /* Remove named semaphore NAME. */
67 extern int sem_unlink (const char *__name) __THROW;
69 /* Wait for SEM being posted.
71 This function is a cancellation point and therefore not marked with
73 extern int sem_wait (sem_t *__sem);
76 /* Similar to `sem_wait' but wait only until ABSTIME.
78 This function is a cancellation point and therefore not marked with
80 extern int sem_timedwait (sem_t *__restrict __sem,
81 const struct timespec *__restrict __abstime);
84 /* Test whether SEM is posted. */
85 extern int sem_trywait (sem_t *__sem) __THROW;
88 extern int sem_post (sem_t *__sem) __THROW;
90 /* Get current value of SEM and store it in *SVAL. */
91 extern int sem_getvalue (sem_t *__restrict __sem, int *__restrict __sval)
97 #endif /* semaphore.h */