The IUnregisterSubdevice interface implements a method to remove a registered subdevice. The port driver implements this interface. To determine whether a port driver supports the IUnregisterSubdevice interface, a miniport driver calls the port driver object's QueryInterface method with REFIID IID_IUnregisterSubdevice. The miniport driver is responsible for releasing the IUnregisterSubdevice object after it is no longer needed. The IUnregisterSubdevice interface inherits from IUnknown.

In Windows Vista, Windows Server 2003 with SP1, and Windows XP with SP2, the following port drivers support the IUnregisterSubdevice interface:

  • WaveCyclic

  • WavePci

  • Topology

  • DMus

  • MIDI

Earlier versions of Windows, including the Windows Server 2003 and Windows XP releases, do not support IUnregisterSubdevice. However, hot-fix packages that contain updated versions of the PortCls system driver (portcls.sys) that support IUnregisterSubdevice are available for Windows Server 2003, Windows XP, and Windows 2000. For more information, see Dynamic Audio Subdevices.

The single method in this interface unregisters a subdevice that was previously registered by a call to the PcRegisterSubdevice routine. PortCls supports PcRegisterSubdevice in Windows 2000 and later, Windows Millennium Edition, and Windows 98.

The IUnregisterSubdevice object maintains its own internal reference to the subdevice to ensure that the corresponding device object is not deleted until all references to the IUnregisterSubdevice object are released.

In addition to the methods that IUnregisterSubdevice inherits from the IUnknown interface, IUnregisterSubdevice supports the following method:




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