C-C++ Code Example: Retrieving PROPID_Q_QUOTA

 

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 retrieves the PROPID_Q_QUOTA property of an existing queue and returns the queue quota to the caller.

This function can return the maximum size of a local private queue from information stored on the local computer, but must retrieve information stored in the directory service to return the maximum size of a local or remote public queue. This function cannot be used to obtain the maximum size of a remote private queue.

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

To retrieve PROPID_Q_QUOTA

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

  2. Define the MQQUEUEPROPS structure.

  3. Specify PROPID_Q_QUOTA.

  4. Initialize the MQQUEUEPROPS structure.

  5. Validate the input parameters provided by the caller.

  6. Call MQGetQueueProperties to retrieve the quota of the queue. If the call fails the returned error code is returned to the caller.

  7. Pass the retrieved queue quota to the caller on return.

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

HRESULT GetQueueQuotaProp(  
                          LPCWSTR wszQueueFormatName,   
                          ULONG *pulValue  
                          )  
{  
  
  // 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_QUOTA property.  
  aQueuePropId[cPropId] = PROPID_Q_QUOTA;         // Property ID  
  aQueuePropVar[cPropId].vt = VT_NULL;            // Type indicator  
  cPropId++;  
  
  // Initialize the MQQUEUEPROPS structure.  
  QueueProps.cProp = cPropId;  
  QueueProps.aPropID = aQueuePropId;  
  QueueProps.aPropVar = aQueuePropVar;  
  QueueProps.aStatus = aQueuePropStatus;  
  
  // Validate the input parameters.  
  if (wszQueueFormatName == NULL || pulValue == NULL)  
  {  
    return MQ_ERROR_INVALID_PARAMETER;  
  }  
  
  // Get the queue properties.  
  hr = MQGetQueueProperties(wszQueueFormatName, &QueueProps);  
  if (FAILED(hr))  
  {  
    return hr;  
  }  
  
  // Set the *pulValue parameter to pass the quota of the queue on return.  
  *pulValue = aQueuePropVar[0].ulVal;  
  return hr;  
}  

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