msgqreceive.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

/*
 *  Message Queue Manager
 *
 *
 *  COPYRIGHT (c) 1989-1999.
 *  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: msgqreceive.c,v 1.5.6.2 2004/05/06 19:20:04 joel Exp $
 */

#include <rtems/system.h>
#include <rtems/score/sysstate.h>
#include <rtems/score/chain.h>
#include <rtems/score/isr.h>
#include <rtems/score/coremsg.h>
#include <rtems/score/object.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
#include <rtems/rtems/status.h>
#include <rtems/rtems/attr.h>
#include <rtems/rtems/message.h>
#include <rtems/rtems/options.h>
#include <rtems/rtems/support.h>

/*PAGE
 *
 *  rtems_message_queue_receive
 *
 *  This directive dequeues a message from the designated message queue
 *  and copies it into the requesting thread's buffer.
 *
 *  Input parameters:
 *    id         - queue id
 *    buffer     - pointer to message buffer
 *    size       - size of message receive
 *    option_set - options on receive
 *    timeout    - number of ticks to wait
 *
 *  Output parameters:
 *    RTEMS_SUCCESSFUL - if successful
 *    error code       - if unsuccessful
 */

rtems_status_code rtems_message_queue_receive(
  Objects_Id            id,
  void                 *buffer,
  unsigned32           *size,
  unsigned32            option_set,
  rtems_interval        timeout
)
{
  register Message_queue_Control *the_message_queue;
  Objects_Locations               location;
  boolean                         wait;
 
  if ( !buffer )
    return RTEMS_INVALID_ADDRESS;

  if ( !size )
    return RTEMS_INVALID_ADDRESS;

  the_message_queue = _Message_queue_Get( id, &location );
  switch ( location ) {

    case OBJECTS_REMOTE:
#if defined(RTEMS_MULTIPROCESSING)
      return _Message_queue_MP_Send_request_packet(
          MESSAGE_QUEUE_MP_RECEIVE_REQUEST,
          id,
          buffer,
          size,
          option_set,
          timeout
        );
#endif

    case OBJECTS_ERROR:
      return RTEMS_INVALID_ID;

    case OBJECTS_LOCAL:
      if ( _Options_Is_no_wait( option_set ) )
        wait = FALSE;
      else
        wait = TRUE;
 
      _CORE_message_queue_Seize(
        &the_message_queue->message_queue,
        the_message_queue->Object.id,
        buffer,
        size,
        wait,
        timeout
      );
      _Thread_Enable_dispatch();
      return _Message_queue_Translate_core_message_queue_return_code(
        _Thread_Executing->Wait.return_code
      );

  }

  return RTEMS_INTERNAL_ERROR;   /* unreached - only to remove warnings */
}