Is it okay to park main thread instead of sleeping or yielding in a forever running script?

I was wondering if there's any downsides to parking the main thread instead of using yield_now or sleep?

Are you just trying to wait forever? If so, loop { thread::park(); } is a perfectly fine way to do it, as is loop { thread::sleep(a_long_time); }. You definitely shouldn’t use loop { thread::yield_now(); }, as that will busy loop and use 100% of the CPU.


I haven't noticed any. Well, other than the documented caveats...

A call to park does not guarantee that the thread will remain parked forever, and callers should be prepared for this possibility.

It may also return spuriously, without consuming the token.