Write an OnEventAlert event handler to take specific actions when an InterBase event is received. 

In the event handler, set CancelAlerts to true to cancel interest in any further events. To start receiving events again, call the GetAutoRegister method. You cannot call RegisterEvents, UnRegisterEvents, GetAutoRegister or SetAutoRegister from within an OnEventAlert event handler. 

OnEventAlert runs as a separate thread to allow for true asynchronous event processing, however, the IBEvents component provides synchronization code to ensure that only one OnEventAlert event handler executes at any one time.