# event_id

The first argument passed to an event handler is always the event ID. It is useful if there are several GPMI events with the same arguments and the script wants to bind them all to the same event handler. In that case using event_id the event handler can determine which event triggered the call. This design is similar to the signal handler documented in signal(2).

The case described above (dispatcher in the event handler) is rare. Most users will bind one event to one function and can safely ignore this argument. Nevertheless it must present as the first argument on the event handler's argument list.