The WdfIoQueueRetrieveNextRequest method retrieves the next available I/O request from a specified I/O queue.
NTSTATUS WdfIoQueueRetrieveNextRequest( [in] WDFQUEUE Queue, [out] WDFREQUEST *OutRequest );
- Queue [in]
A handle to a framework queue object.
- OutRequest [out]
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.
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 );
|Available in version 1.0 and later versions of KMDF.|
|Wdf<MajorVersionNumber>000.sys (see Framework Library Versions.)|