From the NannyMUD documentation
2001-08-12
NAME
connection_hook -AVAILABILITY
This function can be defined in any object. The calls are done from /obj/player.DESCRIPTION
This function is called when a player regains or loses the connection. ARGUMENTS connection_hook( ({ A string, either "lost" or "regain" }), the player )NOTE
This hook isn't called immediately for "lost", but from slow_heart_beat and attack.