WdfIoQueueRetrieveRequestByFileObject method

[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

Queue [in]

A handle to a framework queue object.

FileObject [in]

A handle to a framework file object.

OutRequest [out]

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 codeDescription
STATUS_INVALID_PARAMETER

The driver supplied an invalid handle.

STATUS_NO_MORE_ENTRIES

The framework reached the end of the I/O queue.

STATUS_INVALID_DEVICE_STATE

The specified I/O queue is configured for the parallel dispatching method.

STATUS_WDF_PAUSED

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

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, DriverCreate, KmdfIrql, KmdfIrql2

See also

WdfIoQueueRetrieveFoundRequest
WdfIoQueueRetrieveNextRequest

 

 

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