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/*
* CORE Message Queue Handler
*
* DESCRIPTION:
*
* This package is the implementation of the CORE Message Queue Handler.
* This core object provides task synchronization and communication functions
* via messages passed to queue objects.
*
* COPYRIGHT (c) 1989-1998.
* On-Line Applications Research Corporation (OAR).
* Copyright assigned to U.S. Government, 1994.
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* $Id$
*/
#include <rtems/system.h>
#include <rtems/score/chain.h>
#include <rtems/score/isr.h>
#include <rtems/score/object.h>
#include <rtems/score/coremsg.h>
#include <rtems/score/states.h>
#include <rtems/score/thread.h>
#include <rtems/score/wkspace.h>
#if defined(RTEMS_MULTIPROCESSING)
#include <rtems/score/mpci.h>
#endif
/*PAGE
*
* _CORE_message_queue_Seize
*
* This kernel routine dequeues a message, copies the message buffer to
* a given destination buffer, and frees the message buffer to the
* inactive message pool. The thread will be blocked if wait is TRUE,
* otherwise an error will be given to the thread if no messages are available.
*
* Input parameters:
* the_message_queue - pointer to message queue
* id - id of object we are waitig on
* buffer - pointer to message buffer to be filled
* size - pointer to the size of buffer to be filled
* wait - TRUE if wait is allowed, FALSE otherwise
* timeout - time to wait for a message
*
* Output parameters: NONE
*
* NOTE: Dependent on BUFFER_LENGTH
*
* INTERRUPT LATENCY:
* available
* wait
*/
void _CORE_message_queue_Seize(
CORE_message_queue_Control *the_message_queue,
Objects_Id id,
void *buffer,
unsigned32 *size,
boolean wait,
Watchdog_Interval timeout
)
{
ISR_Level level;
CORE_message_queue_Buffer_control *the_message;
Thread_Control *executing;
executing = _Thread_Executing;
executing->Wait.return_code = CORE_MESSAGE_QUEUE_STATUS_SUCCESSFUL;
_ISR_Disable( level );
if ( the_message_queue->number_of_pending_messages != 0 ) {
the_message_queue->number_of_pending_messages -= 1;
the_message = _CORE_message_queue_Get_pending_message( the_message_queue );
_ISR_Enable( level );
*size = the_message->Contents.size;
_CORE_message_queue_Copy_buffer(the_message->Contents.buffer,buffer,*size );
_CORE_message_queue_Free_message_buffer(the_message_queue, the_message );
return;
}
if ( !wait ) {
_ISR_Enable( level );
executing->Wait.return_code = CORE_MESSAGE_QUEUE_STATUS_UNSATISFIED_NOWAIT;
return;
}
_Thread_queue_Enter_critical_section( &the_message_queue->Wait_queue );
executing->Wait.queue = &the_message_queue->Wait_queue;
executing->Wait.id = id;
executing->Wait.return_argument = (void *)buffer;
executing->Wait.return_argument_1 = (void *)size;
_ISR_Enable( level );
_Thread_queue_Enqueue( &the_message_queue->Wait_queue, timeout );
}
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