WdfIoQueueRetrieveRequestByFileObject function (wdfio.h)
[Applies to KMDF and UMDF]
The WdfIoQueueRetrieveRequestByFileObject method retrieves the next available I/O request, from a specified I/O queue, that is associated with a specified file object.
Syntax
NTSTATUS WdfIoQueueRetrieveRequestByFileObject(
[in] WDFQUEUE Queue,
[in] WDFFILEOBJECT FileObject,
[out] WDFREQUEST *OutRequest
);
Parameters
[in] Queue
A handle to a framework queue object.
[in] FileObject
A handle to a framework file object.
[out] OutRequest
A pointer to a location that receives a handle to a framework request object. If WdfIoQueueRetrieveRequestByFileObject does not return STATUS_SUCCESS, it does not set the location's value.
Return value
WdfIoQueueRetrieveRequestByFileObject returns STATUS_SUCCESS if the operation succeeds. Otherwise, this method might return one of the following values:
Return code | Description |
---|---|
|
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.
Remarks
A driver that has configured an I/O queue for manual or sequential dispatching might call WdfIoQueueRetrieveRequestByFileObject. For more information about using WdfIoQueueRetrieveRequestByFileObject with the manual or sequential dispatching methods, see Dispatching Methods for I/O Requests.
After calling WdfIoQueueRetrieveRequestByFileObject to obtain an I/O request, the driver owns the request and must process the I/O request in some manner.
For more information about the WdfIoQueueRetrieveRequestByFileObject method, see Managing I/O Queues.
Examples
The following code example obtains, from a specified I/O queue, a handle to the next framework request object that is associated with a specified framework file object.
WDFREQUEST request;
status = WdfIoQueueRetrieveRequestByFileObject(
queue,
fileObject,
&request
);
Requirements
Requirement | Value |
---|---|
Target Platform | Universal |
Minimum KMDF version | 1.0 |
Minimum UMDF version | 2.0 |
Header | wdfio.h (include Wdf.h) |
Library | Wdf01000.sys (KMDF); WUDFx02000.dll (UMDF) |
IRQL | <= DISPATCH_LEVEL |
DDI compliance rules | DoubleCompletion(kmdf), DriverCreate(kmdf), KmdfIrql(kmdf), KmdfIrql2(kmdf), KmdfIrqlExplicit(kmdf) |