HOWTO: Send in a MSMQ Single-Message Transaction

• Microsoft Message Queue Server version 1.0

SUMMARY

As part of its internal transaction support, Microsoft Message Queue Server (MSMQ) provides specific functionality to handle cases where an MSMQ application wants to send only a single message in a single transaction. One reason to do this is to ensure exactly-once delivery, without needing to coordinate with other activities into a single transaction.

The benefits of using this functionality are:

• Speed, compared to using an external transaction coordinator.
• Simplified application code.
• Delivery that is assured to occur exactly once.

MORE INFORMATION

The following code sample illustrates sending a single-message transaction using the ActiveX methods:

   Dim qinfo As New MSMQQueueInfo
   Dim q As MSMQQueue
   Dim m As New MSMQMessage

   qinfo.PathName = "MachineName\TransactionalQueueName"
   Set q = qinfo.Open(MQ_SEND_ACCESS, MQ_DENY_NONE)
   m.Send q, MQ_SINGLE_MESSAGE
   q.Close

   void TransactSend(QUEUEHANDLE h, MQMSGPROPS * pMsgProps)
   {
      HRESULT hr;
      printf ("\nStarting transaction...\n\n");
      //////////////////////////////////////
      // Call MQSendMessage to send a transactional message to
      // the destination queue.
      //////////////////////////////////////
      hr = MQSendMessage(h,                  // Handle to dest queue
                        &msgprops,           // Pointer to MQMSGPROPS
                        MQ_SINGLE_MESSAGE);  // Implicit internal
                                             // transactional message.
      if (FAILED(hr))
      {
      printf("\nFailed in MQSendMessage(). hresult- %lxh\n", (DWORD) hr) ;
      }
      else
      {
          printf ("Committing the transaction...   ");
      }
     }

REFERENCES

For more information and sample code regarding MSMQ transactions, see the "MQSendMessage," "MSMQ Internal Transactions," and "Transaction Programming Considerations" topics in the SDK online Help.