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/**
* @file
*
* @brief Lock a Semaphore
* @ingroup POSIX_SEMAPHORE POSIX Semaphores Support
*/
/*
* COPYRIGHT (c) 1989-2008.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/posix/semaphoreimpl.h>
#include <rtems/score/todimpl.h>
/*
* 11.2.6 Lock a Semaphore, P1003.1b-1993, p.226
*
* NOTE: P1003.4b/D8 adds sem_timedwait(), p. 27
*/
int sem_timedwait(
sem_t *__restrict _sem,
const struct timespec *__restrict abstime
)
{
Sem_Control *sem;
Thread_queue_Context queue_context;
ISR_Level level;
Thread_Control *executing;
unsigned int count;
POSIX_SEMAPHORE_VALIDATE_OBJECT( _sem );
sem = _Sem_Get( &_sem->_Semaphore );
_Thread_queue_Context_initialize( &queue_context );
_Thread_queue_Context_ISR_disable( &queue_context, level );
executing = _Sem_Queue_acquire_critical( sem, &queue_context );
count = sem->count;
if ( RTEMS_PREDICT_TRUE( count > 0 ) ) {
sem->count = count - 1;
_Sem_Queue_release( sem, level, &queue_context );
return 0;
} else {
Status_Control status;
_Thread_queue_Context_set_thread_state(
&queue_context,
STATES_WAITING_FOR_SEMAPHORE
);
_Thread_queue_Context_set_enqueue_timeout_realtime_timespec(
&queue_context,
abstime
);
_Thread_queue_Context_set_ISR_level( &queue_context, level );
_Thread_queue_Enqueue(
&sem->Queue.Queue,
SEMAPHORE_TQ_OPERATIONS,
executing,
&queue_context
);
status = _Thread_Wait_get_status( executing );
return _POSIX_Zero_or_minus_one_plus_errno( status );
}
}
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