This member function unregisters an application object previously registered for communication events with the RegisterCommEvent() function. A registered application notify object should not be destroyed without first calling this function to unregister it. If there is no notify object currently registered, or the registered object is not the NotifyObject passed in, this function does nothing (no error is thrown).

When a notify object is unregistered, its NotifyStop() member function will be called.

See the description of ECLCommNotify Class for more information.