IWDFDevice2::GetDeviceStackIoTypePreference method

The GetDeviceStackIoTypePreference method retrieves the buffer access methods that the framework is using for a device.

Syntax

C++


void GetDeviceStackIoTypePreference(
  [out]  WDF_DEVICE_IO_TYPE *ReadWritePreference,
  [out]  WDF_DEVICE_IO_TYPE *IoControlPreference
);

Parameters

ReadWritePreference [out]: A pointer to a driver-allocated location that receives a WDF_DEVICE_IO_TYPE-typed value. This value identifies the buffer access method that the framework is using for a device's read and write requests.
IoControlPreference [out]: A pointer to a driver-allocated location that receives a WDF_DEVICE_IO_TYPE-typed value. This value that identifies the buffer access method that the framework is using for a device's I/O control requests.

Return value

None.

Remarks

If your driver calls GetDeviceStackIoTypePreference before the PnP manager has loaded all of the device's drivers, the values that GetDeviceStackIoTypePreference retrieves might not be the values that it actually uses.

For more information about how the framework chooses a buffer access method, see How UMDF Chooses a Buffer Access Method for an I/O Request.

Examples

The following code example retrieves the buffer access methods that the framework is using for a device.


WDF_DEVICE_IO_TYPE ReadWriteAccessMethod;
WDF_DEVICE_IO_TYPE IoControlAccessMethod;

Device2->GetDeviceStackIoTypePreference(&ReadWriteAccessMethod,
                                        &IoControlAccessMethod);

Requirements

End of support	Unavailable in UMDF 2.0 and later.
Minimum UMDF version	1.9
Header	Wudfddi.h (include Wudfddi.h)
DLL	WUDFx.dll