WdfObjectDereferenceActual method

[Applies to KMDF and UMDF]

The WdfObjectDereferenceActual method decrements the reference count for a specified framework object and assigns a tag value, line number, and file name to the reference.

Syntax


VOID WdfObjectDereferenceActual(
  [in]            WDFOBJECT Handle,
  [in, optional]  PVOID Tag,
  [in]            LONG Line,
  [in, optional]  PCHAR File
);

Parameters

Handle [in]

A handle to a framework object.

Tag [in, optional]

A driver-defined value that identifies an object reference. The tag value must match a tag value that the driver previously supplied to WdfObjectReferenceActual.

Line [in]

A numeric value that represents a line number in a driver source file.

File [in, optional]

A pointer to a null-terminated text string that represents the name of a driver source file. This parameter is optional and can be NULL.

Return value

None.

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

Remarks

If the object's reference count becomes zero, the object might be deleted before WdfObjectDereferenceActual returns.

Calling WdfObjectDereferenceActual or WdfObjectDereferenceWithTag instead of WdfObjectDereference provides additional information (tag string, line number, and file name) to Microsoft debuggers. WdfObjectDereferenceActual allows your driver to specify the line number and file name, while WdfObjectDereferenceWithTag uses the driver's current line number and file name.

You can view the tag, line number, and file name values by using the !wdftagtracker debugger extension. The debugger extension displays the tag value as both a pointer and a series of characters. For more information about debugger extensions, see Debugging a KMDF Driver.

For more information about object reference counts, see Framework Object Life Cycle.

Examples

The following code example decrements an object's reference count and assigns a tag value, line number, and file name to the reference.


WdfObjectDereferenceActual(
                           object,
                           pTag,
                           line,
                           FILE_NAME
                           );

Requirements

Minimum KMDF version

1.0

Minimum UMDF version

2.0

Header

Wdfobject.h (include Wdf.h)

Library

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

IRQL

<=DISPATCH_LEVEL

DDI compliance rules

DriverCreate

See also

WdfObjectDereference
WdfObjectReferenceActual

 

 

Send comments about this topic to Microsoft

Show:
© 2014 Microsoft