WdfRequestIsReserved function (wdfrequest.h)

Artikel
04/18/2022

[Applies to KMDF only]

The WdfRequestIsReserved method determines whether a specified request object is one that the framework reserved to support guaranteed forward progress during low-memory situations.

Syntax

BOOLEAN WdfRequestIsReserved(
  [in] WDFREQUEST Request
);

Parameters

[in] Request

A handle to a framework request object.

Return value

WdfRequestIsReserved returns TRUE if the specified request object is one that the framework pre-allocated for low-memory situations. Otherwise the method returns FALSE.

Remarks

For more information about the WdfRequestIsReserved method, see Guaranteeing Forward Progress of I/O Operations.

Examples

The following code example determines whether a request object that a driver's EvtIoRead callback function has received is one that the driver created for low-memory situations.

VOID
  MyIoRead (
    IN WDFQUEUE  Queue,
    IN WDFREQUEST  Request,
    IN size_t  Length
    )
  {...
  if (WdfRequestIsReserved(Request)) {
  // Low memory situation exists.
  ...
  }
  else {
  // Low memory situation does not exist.
  ...
  }

  ...}

Requirements

Requirement	Value
Target Platform	Universal
Minimum KMDF version	1.9
Header	wdfrequest.h (include Wdf.h)
Library	Wdf01000.sys (see Framework Library Versioning.)
IRQL	<=DISPATCH_LEVEL
DDI compliance rules	DriverCreate(kmdf)

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