WdfDeviceGetIoTarget function

Description

[Applies to KMDF and UMDF]

The WdfDeviceGetIoTarget method returns a handle to a function or filter driver's local I/O target, for a specified device.

Parameters

Device [in]

A handle to a framework device object.

Return value

If the operation succeeds, WdfDeviceGetIoTarget returns a handle to a framework I/O target object. If the specified framework device object represents a PDO, the method returns NULL.

A bug check occurs if the driver supplies an invalid object handle.

Remarks

When a UMDF driver sends a driver-created request to a local I/O target, the request has no associated file object. Some lower targets, such as a HIDClass-enumerated raw PDO, fail requests that have no associated file object. In this situation, a UMDF driver can specify WdfIoTargetOpenLocalTargetByFile to create an I/O target that represents the lower stack (just like a local target) using a file handle. As a result, any driver-created requests sent to this I/O target are associated with the file object corresponding to the handle opened.

To do so, call the WDF_IO_TARGET_OPEN_PARAMS_INIT_OPEN_BY_FILE function before calling WdfIoTargetOpen.

For more information about I/O targets, see Using I/O Targets.

Examples

The following code example obtains a handle to a specified device's local I/O target.

WDFIOTARGET  ioTargetHandle;

ioTargetHandle = WdfDeviceGetIoTarget(device);