Pilot Sleeping in the Cockpit

Some countries like Canada and Australia allow for pilots to take naps in the cockpit. The idea is that the pilot can sleep for no more than 40 minutes, must wake up at least half an hour before the descent of landing. So basically, it's really strict rules. But what they call it is a controlled rest in position, CRIP. And then they can go down for a nap sitting in their position without worry that they might affect the controls as long as obviously they have a co-pilot next to them.