Gets a reference to the RegisterFunctions event
CXlRegisterFunctionsEvent& RegisterFunctionsEvent( );
The function returns a reference to the application's RegisterFunctions event, which is of type CXlRegisterFunctionsEvent.
The RegisterFunctions event is raised just before the XLL's add-in functions are registered is opened, giving observers a chance to modify function definitions before the are registered with Excel. All registered observers receive the event via the CXlEventObserver::Update method.
Observers should register for this event early in the life of the XLL. Registration can be done explicitly during CXllApp::InitInstance, or automatically by creating an instance of CXlRegisterFunctionsEventStaticObserver.