Expand Minimize

WdfRequestIsFrom32BitProcess method

[Applies to KMDF and UMDF]

The WdfRequestIsFrom32BitProcess method checks whether the originator of a specified I/O request is a 32-bit user-mode application.

Syntax


BOOLEAN WdfRequestIsFrom32BitProcess(
  [in]  WDFREQUEST Request
);

Parameters

Request [in]

A handle to a framework request object.

Return value

On 64-bit systems,WdfRequestIsFrom32BitProcess returns TRUE if the originator of the current I/O request is a 32-bit user-mode process, and FALSE otherwise. On 32-bit systems, WdfRequestIsFrom32BitProcess always returns TRUE.

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

Remarks

Drivers can call WdfRequestIsFrom32BitProcess to determine whether an I/O request is likely to contain data elements that need to be converted, or "thunked," before they can be used in a 64-bit driver.

The specified request handle must have been obtained from one of the driver's I/O queues and not from a call to WdfRequestCreate.

Examples

The following code example determines if an I/O request came from a 32-bit application.


VOID
MyEvtIoRead(
    IN WDFQUEUE  Queue,
    IN WDFREQUEST  Request,
    IN size_t  Length
    )
{
...
    if (WdfRequestIsFrom32BitProcess(Request)) {
        //
        // The driver is running on a 64-bit computer and the 
        // I/O request came from a 32-bit application.
        //
...
    }
...
}

Requirements

Minimum KMDF version

1.0

Minimum UMDF version

2.0

Header

Wdfrequest.h (include Wdf.h)

Library

Wdf01000.sys (KMDF);
WUDFx02000.dll (UMDF)

IRQL

<=DISPATCH_LEVEL

DDI compliance rules

DriverCreate, InvalidReqAccess, InvalidReqAccessLocal, KmdfIrql, KmdfIrql2

See also

WdfRequestCreate

 

 

Send comments about this topic to Microsoft

Show:
© 2014 Microsoft