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/*
* NOTE: The structure of the routines is identical to that of POSIX
* Message_queues to leave the option of having unnamed message
* queues at a future date. They are currently not part of the
* POSIX standard but unnamed message_queues are. This is also
* the reason for the apparently unnecessary tracking of
* the process_shared attribute. [In addition to the fact that
* it would be trivial to add pshared to the mq_attr structure
* and have process private message queues.]
*
* This code ignores the O_RDONLY/O_WRONLY/O_RDWR flag at open
* time.
*/
/*
* 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.com/license/LICENSE.
*
* $Id$
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdarg.h>
#include <pthread.h>
#include <limits.h>
#include <errno.h>
#include <fcntl.h>
#include <mqueue.h>
#include <rtems/system.h>
#include <rtems/score/watchdog.h>
#include <rtems/seterr.h>
#include <rtems/posix/mqueue.h>
#include <rtems/posix/time.h>
/*PAGE
*
* 15.2.5 Receive a Message From a Message Queue, P1003.1b-1993, p. 279
*
* NOTE: P1003.4b/D8, p. 45 adds mq_timedreceive().
*/
ssize_t mq_timedreceive(
mqd_t mqdes,
char *msg_ptr,
size_t msg_len,
unsigned int *msg_prio,
const struct timespec *abstime
)
{
Watchdog_Interval ticks;
bool do_wait;
/*
* POSIX requires that blocking calls with timeouts that take
* an absolute timeout must ignore issues with the absolute
* time provided if the operation would otherwise succeed.
* So we check the abstime provided, and hold on to whether it
* is valid or not. If it isn't correct and in the future,
* then we do a polling operation and convert the UNSATISFIED
* status into the appropriate error.
*/
switch ( _POSIX_Absolute_timeout_to_ticks( abstime, &ticks ) ) {
case POSIX_ABSOLUTE_TIMEOUT_INVALID:
case POSIX_ABSOLUTE_TIMEOUT_IS_IN_PAST:
case POSIX_ABSOLUTE_TIMEOUT_IS_NOW:
do_wait = false;
break;
case POSIX_ABSOLUTE_TIMEOUT_IS_IN_FUTURE:
default: /* only to silence warnings */
do_wait = true;
break;
}
return _POSIX_Message_queue_Receive_support(
mqdes,
msg_ptr,
msg_len,
msg_prio,
do_wait,
ticks
);
}
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