Function svcRtxMessageQueueGet

source/rtos2/RTX/Source/rtx_msgqueue.c:468–544

Get a Message from a Queue or timeout if Queue is empty. \note API identical to osMessageQueueGet

/// Get a Message from a Queue or timeout if Queue is empty.
/// \note API identical to osMessageQueueGet
static osStatus_t svcRtxMessageQueueGet (osMessageQueueId_t mq_id, void *msg_ptr, uint8_t *msg_prio, uint32_t timeout) {
  os_message_queue_t *mq = osRtxMessageQueueId(mq_id);
  os_message_t       *msg;
  os_thread_t        *thread;
  uint32_t           *reg;
  const void         *ptr;
  osStatus_t          status;

  // Check parameters
  if ((mq == NULL) || (mq->id != osRtxIdMessageQueue) || (msg_ptr == NULL)) {
    EvrRtxMessageQueueError(mq, (int32_t)osErrorParameter);
    //lint -e{904} "Return statement before end of function" [MISRA Note 1]
    return osErrorParameter;
  }

  // Get Message from Queue
  msg = MessageQueueGet(mq);
  if (msg != NULL) {
    MessageQueueRemove(mq, msg);
    // Copy Message
    memcpy(msg_ptr, &msg[1], mq->msg_size);
    if (msg_prio != NULL) {
      *msg_prio = msg->priority;
    }
    EvrRtxMessageQueueRetrieved(mq, msg_ptr);
    // Free memory
    msg->id = osRtxIdInvalid;
    (void)osRtxMemoryPoolFree(&mq->mp_info, msg);
    // Check if Thread is waiting to send a Message
    if (mq->thread_list != NULL) {
      // Try to allocate memory
      //lint -e{9079} "conversion from pointer to void to pointer to other type" [MISRA Note 5]
      msg = osRtxMemoryPoolAlloc(&mq->mp_info);
      if (msg != NULL) {
        // Wakeup waiting Thread with highest Priority
        thread = osRtxThreadListGet(osRtxObject(mq));
        osRtxThreadWaitExit(thread, (uint32_t)osOK, TRUE);
        // Copy Message (R2: const void *msg_ptr, R3: uint8_t msg_prio)
        reg = osRtxThreadRegPtr(thread);
        //lint -e{923} "cast from unsigned int to pointer"
        ptr = (const void *)reg[2];
        memcpy(&msg[1], ptr, mq->msg_size);
        // Store Message into Queue
        msg->id       = osRtxIdMessage;
        msg->flags    = 0U;
        msg->priority = (uint8_t)reg[3];
        MessageQueuePut(mq, msg);
        EvrRtxMessageQueueInserted(mq, ptr);
      }
    }
    status = osOK;
  } else {
    // No Message available
    if (timeout != 0U) {
      EvrRtxMessageQueueGetPending(mq, msg_ptr, timeout);
      // Suspend current Thread
      if (osRtxThreadWaitEnter(osRtxThreadWaitingMessageGet, timeout)) {
        osRtxThreadListPut(osRtxObject(mq), osRtxThreadGetRunning());