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      1 /* Copyright (C) 2002, 2003 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, write to the Free
     16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
     17    02111-1307 USA.  */
     18 
     19 #ifndef _SEMAPHORE_H
     20 #define _SEMAPHORE_H	1
     21 
     22 #include <features.h>
     23 #include <sys/types.h>
     24 #ifdef __USE_XOPEN2K
     25 # define __need_timespec
     26 # include <time.h>
     27 #endif
     28 
     29 /* Get the definition for sem_t.  */
     30 #include <bits/semaphore.h>
     31 
     32 
     33 __BEGIN_DECLS
     34 
     35 /* Initialize semaphore object SEM to VALUE.  If PSHARED then share it
     36    with other processes.  */
     37 extern int sem_init (sem_t *__sem, int __pshared, unsigned int __value)
     38      __THROW;
     39 /* Free resources associated with semaphore object SEM.  */
     40 extern int sem_destroy (sem_t *__sem) __THROW;
     41 
     42 /* Open a named semaphore NAME with open flags OFLAG.  */
     43 extern sem_t *sem_open (__const char *__name, int __oflag, ...) __THROW;
     44 
     45 /* Close descriptor for named semaphore SEM.  */
     46 extern int sem_close (sem_t *__sem) __THROW;
     47 
     48 /* Remove named semaphore NAME.  */
     49 extern int sem_unlink (__const char *__name) __THROW;
     50 
     51 /* Wait for SEM being posted.
     52 
     53    This function is a cancellation point and therefore not marked with
     54    __THROW.  */
     55 extern int sem_wait (sem_t *__sem);
     56 
     57 #ifdef __USE_XOPEN2K
     58 /* Similar to `sem_wait' but wait only until ABSTIME.
     59 
     60    This function is a cancellation point and therefore not marked with
     61    __THROW.  */
     62 extern int sem_timedwait (sem_t *__restrict __sem,
     63 			  __const struct timespec *__restrict __abstime);
     64 #endif
     65 
     66 /* Test whether SEM is posted.  */
     67 extern int sem_trywait (sem_t *__sem) __THROW;
     68 
     69 /* Post SEM.  */
     70 extern int sem_post (sem_t *__sem) __THROW;
     71 
     72 /* Get current value of SEM and store it in *SVAL.  */
     73 extern int sem_getvalue (sem_t *__restrict __sem, int *__restrict __sval)
     74      __THROW;
     75 
     76 
     77 __END_DECLS
     78 
     79 #endif	/* semaphore.h */
     80