For networking, it's using epoll() under the scenes; depends on what exact non-blocking operation you're using, though. See this very very old HN thread: http

For networking, it's using epoll() under the scenes; depends on what exact non-blocking operation you're using, though. See this very very old HN thread: https://news.ycombinator.com/item?id=3565703 https://news.ycombinator.com/item?id=3565703 (Hopefully the standard library has improved since then.)