[pqh]

Use case for labelled breaks: collision detection in video game, where anything colliding with anything else ends the game, resets a counter, spawns Godzilla, who knows. With labels, you can break out of the top loop very efficiently.

[throwanem]

You can't efficiently get back into it, though, which can be a problem for a game's event loop. If you wrap it in a function, you can return from that function anywhere inside the loop, and let its caller handle whatever state change incurred the exit and then restart the loop, if it wants, by calling the function again.

On the other hand, if the event loop's job also includes rendering the game's UI, then leaving it by any means will freeze the display until it's restarted. That's probably bad too, although I suppose in theory it could be turned into a game mechanic. Absent that, this technique might make more sense in a case where you're running the exitable loop in question on a secondary thread (i.e. a worker), and doing things with it which can be safely interrupted - maybe changing levels or something, where the player isn't expecting to do anything during a UI transition, and you need to await the arrival of some resources over the network and then set up the game state before restarting the event loop to resume normal play? I don't know, that's a bit contrived and probably flawed in a critical way, but I think it makes the same basic sense as offloading heavy and necessarily synchronous work to a worker thread does in general.