WdfIoQueueDrainSynchronously - NtDoc
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// wdfio.h
VOID WdfIoQueueDrainSynchronously(
[in] WDFQUEUE Queue
);
View the official Windows Driver Kit DDI referenceNo description available.
[Applies to KMDF and UMDF]
The WdfIoQueueDrainSynchronously method causes the framework to stop queuing I/O requests to an I/O queue, while allowing already-queued requests to be delivered and processed. The method returns after all requests are completed or canceled.
Queue [in]A handle to a framework queue object.
A bug check occurs if the driver supplies an invalid object handle.
After a driver calls WdfIoQueueDrainSynchronously, the framework stops adding I/O requests to the specified queue. If the framework receives additional requests for the queue, it completes them with a completion status value of STATUS_INVALID_DEVICE_STATE.
The driver should not call another method that changes queue state, such as WdfIoQueuePurge or WdfIoQueueStart, before the call to WdfIoQueueDrainSynchronously has returned.
As a best practice, you should only call WdfIoQueueDrainSynchronously when you are certain that the queue's pending I/O requests will complete in a timely fashion. Otherwise, use WdfIoQueuePurgeSynchronously. For more information, see Managing I/O Queues.
After a driver has drained an I/O queue, it can restart the queue by calling WdfIoQueueStart.
Do not call WdfIoQueueDrainSynchronously from the following queue object event callback functions, regardless of the queue with which the event callback function is associated:
EvtIoDefault EvtIoDeviceControl EvtIoInternalDeviceControl EvtIoRead EvtIoWrite
The following code example drains an I/O queue.
WdfIoQueueDrainSynchronously(queue);