WdfFdoInitSetFilter method
[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
- DeviceInit [in]
-
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.
If a driver calls WdfFdoInitSetFilter, it should not call WdfDeviceInitSetIoType, WdfDeviceInitSetPowerInrush, or WdfDeviceInitSetPowerPageable because the framework ignores the information provided by these calls. Instead, the framework obtains this information from the next-lower device object in the driver's device stack.
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
|
Minimum KMDF version | 1.0 |
|---|---|
|
Minimum UMDF version | 2.0 |
|
Header |
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Library |
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IRQL | PASSIVE_LEVEL |
|
DDI compliance rules | DeviceInitAPI, DriverCreate, DrvAckIoStop, KmdfIrql, KmdfIrql2 |
See also
