C-C++ Code Example: Setting PROPID_Q_LABEL

 

Updated: July 19, 2016

Applies To: Windows 10, Windows 7, Windows 8, Windows 8.1, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2, Windows Server Technical Preview, Windows Vista

This example provides an application-defined function that sets the PROPID_Q_LABEL property of an existing queue based on a given queue label provided by the caller.

A direct format name can be passed to this function only for a local private queue.

To set PROPID_Q_LABEL

  1. Validate the input parameters provided by the caller.

  2. Define the maximum number of queue properties to be specified and the queue property counter.

  3. Define the MQQUEUEPROPS structure.

  4. Specify PROPID_Q_LABEL.

  5. Initialize the MQQUEUEPROPS structure.

  6. Call MQSetQueueProperties to set the label of the queue. If the call fails the returned error code is returned to the caller.

The following code example can be run on all versions of Message Queuing.

HRESULT SetQueueLabelProp(  
                          LPCWSTR wszQueueFormatName,   
                          LPWSTR wszValue  
                          )  
{  
  
  // Validate the input parameters.  
  if (wszQueueFormatName == NULL || wszValue == NULL)  
  {  
    return MQ_ERROR_INVALID_PARAMETER;  
  }  
  
  // Define the maximum number of queue properties and a property counter.  
  const int NUMBEROFPROPERTIES = 1;  
  DWORD cPropId=0;  
  
  // Define a queue property structure.  
  MQQUEUEPROPS   QueueProps;  
  QUEUEPROPID    aQueuePropId[NUMBEROFPROPERTIES];  
  MQPROPVARIANT  aQueuePropVar[NUMBEROFPROPERTIES];  
  HRESULT        aQueuePropStatus[NUMBEROFPROPERTIES];  
  HRESULT hr = MQ_OK;  
  
  // Specify the PROPID_Q_LABEL property.  
  aQueuePropId[cPropId] = PROPID_Q_LABEL;         // Property ID  
  aQueuePropVar[cPropId].vt = VT_LPWSTR;          // Type indicator  
  aQueuePropVar[cPropId].pwszVal= wszValue;       // Queue label  
  cPropId++;  
  
  // Initialize the MQQUEUEPROPS structure.  
  QueueProps.cProp = cPropId;  
  QueueProps.aPropID = aQueuePropId;  
  QueueProps.aPropVar = aQueuePropVar;  
  QueueProps.aStatus = aQueuePropStatus;  
  
  // Set the queue properties.  
  hr = MQSetQueueProperties(wszQueueFormatName, &QueueProps);  
  return hr;  
}  

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