EVT_WDF_REQUEST_COMPLETION_ROUTINE callback function (wdfrequest.h)

[Applies to KMDF and UMDF]

A driver's CompletionRoutine event callback function executes when another driver completes a specified I/O request.

Syntax

EVT_WDF_REQUEST_COMPLETION_ROUTINE EvtWdfRequestCompletionRoutine;

VOID EvtWdfRequestCompletionRoutine(
 [in] WDFREQUEST Request,
 [in] WDFIOTARGET Target,
 [in] PWDF_REQUEST_COMPLETION_PARAMS Params,
 [in] WDFCONTEXT Context
)
{...}

Parameters

[in] Request

A handle to a framework request object that represents the completed I/O request.

[in] Target

A handle to an I/O target object that represents the I/O target that completed the request.

[in] Params

A pointer to a WDF_REQUEST_COMPLETION_PARAMS structure that contains information about the completed request. See note below regarding validity of the completion parameters.

[in] Context

Driver-supplied context information, which the driver specified in a previous call to WdfRequestSetCompletionRoutine.

Return value

None

Remarks

To register a CompletionRoutine callback function for an I/O request, a driver must call WdfRequestSetCompletionRoutine. For more information about this callback function, see Completing I/O Requests.

The completion parameters structure is fully populated with valid information only if the driver formatted the request by calling one of the following:

• WdfIoTargetFormatXxx methods, for example WdfIoTargetFormatRequestForRead
• WdfUsbTargetDeviceFormatRequestForXxx methods, for example WdfUsbTargetDeviceFormatRequestForString
• WdfUsbTargetPipeFormatRequestForXxx methods, for example WdfUsbTargetPipeFormatRequestForWrite

If the driver formatted the request using either WdfRequestFormatRequestUsingCurrentType or WdfRequestWdmFormatUsingStackLocation, only the IoStatus field in the completion parameters structure is valid.

A KMDF driver's CompletionRoutine can run at IRQL <= DISPATCH_LEVEL regardless of the ExecutionLevel specified in the WDF_OBJECT_ATTRIBUTES structure for the I/O request object.

Examples

The function type is declared in Wdfrequest.h, as follows.

typedef VOID
 (EVT_WDF_REQUEST_COMPLETION_ROUTINE)(
 IN WDFREQUEST Request,
 IN WDFIOTARGET Target,
 IN PWDF_REQUEST_COMPLETION_PARAMS Params,
 IN WDFCONTEXT Context
 );

To define a CompletionRoutine callback function that is named MyCompletionRoutine, you must first provide a function declaration that SDV and other verification tools require, as follows:

EVT_WDF_REQUEST_COMPLETION_ROUTINE MyCompletionRoutine;

Then, implement your callback function as follows:

VOID
 MyCompletionRoutine (
 IN WDFREQUEST Request,
 IN WDFIOTARGET Target,
 IN PWDF_REQUEST_COMPLETION_PARAMS Params,
 IN WDFCONTEXT Context
 )
 {...}

Requirements

See also

WDF_REQUEST_COMPLETION_PARAMS

WdfRequestSetCompletionRoutine