[Applies to KMDF and UMDF]
The WdfIoQueueRetrieveNextRequest method retrieves the next available I/O request from a specified I/O queue.
NTSTATUS WdfIoQueueRetrieveNextRequest( WDFQUEUE Queue, WDFREQUEST *OutRequest );
A handle to a framework queue object.
A pointer to a location that receives a handle to a framework request object. If the queue is empty or the last request has been retrieved, this parameter receives NULL.
WdfIoQueueRetrieveNextRequest returns STATUS_SUCCESS if the operation succeeds. Otherwise, this method might return one of the following values:
||The driver supplied an invalid handle.|
||The framework reached the end of the I/O queue.|
||The specified I/O queue is configured for the parallel dispatching method.|
||The specified I/O queue is power-managed and its device is in a low-power state, or the specified queue is stopped.|
This method also might return other NTSTATUS values.
A bug check occurs if the driver supplies an invalid object handle.
If a driver configures an I/O queue for manual dispatching of I/O requests, the driver typically calls WdfIoQueueRetrieveNextRequest to obtain requests from the queue. A driver that has configured an I/O queue for sequential dispatching might also call WdfIoQueueRetrieveNextRequest. For more information about using WdfIoQueueRetrieveNextRequest with the manual or sequential dispatching methods, see Dispatching Methods for I/O Requests.
For more information about the WdfIoQueueRetrieveNextRequest method, see Managing I/O Queues.
The following code example obtains a handle to the next request object that is contained in a device's I/O queue.
NTSTATUS status; WDFREQUEST request; status = WdfIoQueueRetrieveNextRequest( pDeviceContext->ReadQueue, &request );
|Minimum KMDF version||1.0|
|Minimum UMDF version||2.0|
|Header||wdfio.h (include Wdf.h)|
|Library||Wdf01000.sys (KMDF); WUDFx02000.dll (UMDF)|
|DDI compliance rules||DoubleCompletion, DriverCreate, KmdfIrql, KmdfIrql2, wdfioqueueretrievenextrequest|