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/**
* @file
*
* @brief Message Queue Attributes
* @ingroup POSIXAPI
*/
/*
* 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) 1989-2011.
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/posix/mqueueimpl.h>
/*
* 15.2.8 Get Message Queue Attributes, P1003.1b-1993, p. 283
*/
int mq_getattr(
mqd_t mqdes,
struct mq_attr *mqstat
)
{
POSIX_Message_queue_Control *the_mq;
Thread_queue_Context queue_context;
if ( mqstat == NULL ) {
rtems_set_errno_and_return_minus_one( EINVAL );
}
the_mq = _POSIX_Message_queue_Get( mqdes, &queue_context );
if ( the_mq == NULL ) {
rtems_set_errno_and_return_minus_one( EBADF );
}
_CORE_message_queue_Acquire_critical(
&the_mq->Message_queue,
&queue_context
);
if ( the_mq->open_count == 0 ) {
_CORE_message_queue_Release( &the_mq->Message_queue, &queue_context );
rtems_set_errno_and_return_minus_one( EBADF );
}
/*
* Return the old values.
*/
mqstat->mq_flags = the_mq->oflag;
mqstat->mq_msgsize = the_mq->Message_queue.maximum_message_size;
mqstat->mq_maxmsg = the_mq->Message_queue.maximum_pending_messages;
mqstat->mq_curmsgs = the_mq->Message_queue.number_of_pending_messages;
_CORE_message_queue_Release( &the_mq->Message_queue, &queue_context );
return 0;
}
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