WdfFdoInitSetFilter function (wdffdo.h)
[Applies to KMDF and UMDF]
The WdfFdoInitSetFilter method identifies the calling driver as an upper-level or lower-level filter driver, for a specified device.
Syntax
void WdfFdoInitSetFilter(
[in] PWDFDEVICE_INIT DeviceInit
);
Parameters
[in] DeviceInit
A pointer to a WDFDEVICE_INIT structure that the driver obtained from its EvtDriverDeviceAdd callback function.
Return value
None
Remarks
Filter drivers typically process some I/O requests, but they simply pass most requests to the next driver in the driver stack. If the framework receives a request for one of your driver's devices, and if the driver has not created an I/O queue to receive requests that match the request type, the way the framework processes the request depends on whether the driver has called WdfFdoInitSetFilter:
- If a driver calls WdfFdoInitSetFilter, the driver framework forwards the request to the next driver.
- If a driver does not call WdfFdoInitSetFilter, the framework completes the request with a status value of STATUS_INVALID_DEVICE_REQUEST.
The driver must call WdfFdoInitSetFilter before calling WdfDeviceCreate. For more information about calling WdfDeviceCreate, see Creating a Framework Device Object. In addition, the driver must call WdfFdoInitSetFilter before returning from its EvtDriverDeviceAdd callback function.
For more information about WdfFdoInitSetFilter, see Creating Device Objects in a Filter Driver, Creating I/O Queues and Forwarding I/O Requests.
Examples
The following code example identifies the calling driver as a filter driver for the specified device.
WdfFdoInitSetFilter(DeviceInit);
Requirements
Requirement | Value |
---|---|
Target Platform | Universal |
Minimum KMDF version | 1.0 |
Minimum UMDF version | 2.0 |
Header | wdffdo.h (include Wdf.h) |
Library | Wdf01000.sys (KMDF); WUDFx02000.dll (UMDF) |
IRQL | PASSIVE_LEVEL |
DDI compliance rules | DeviceInitAPI(kmdf), DriverCreate(kmdf), DrvAckIoStop(kmdf), KmdfIrql(kmdf), KmdfIrql2(kmdf), KmdfIrqlExplicit(kmdf) |