If the exit manager specified in a call to the Set_Exit_Information service is not available, the system returns an error code. If and when the exit manager becomes available, the system gives control to the NOTIFICATION exit routine, if provided; the routine can reissue the call to the Set_Exit_Information service.

The NOTIFICATION exit routine has a second use. If an exit manager becomes unavailable, the system gives control to the NOTIFICATION exit routine, if provided.