I don't think this is blindingly obvious. I always imagined something 'called us', then just returning from that would be enough to get everything shutdown. C

I don't think this is blindingly obvious. I always imagined something 'called us', then just returning from that would be enough to get everything shutdown. Certainly when I wrote 6502 code, or 68000 code, I would just return. On the iPhone, you get advised you are shutting down, do your clean-up, then someone shuts down the message loop and you are gone.