execl()

• Replace existing process with a new one
• File descriptors remain open
• Used by numerous MUDs
  • Players happily slashing up monsters
  • Administrator enters command
  • Entire game is paused (players are interrupted)
  • Player data is saved, world-state is not
  • Process re-executes
  • Player data loaded from disk, world-state initialized from defaults
  • Game-play continues (players complain)