[LtdJorge]

Depends, on Linux you can call set_nonblocking on a TcpListener and get a WouldBlock error whenever a read would block. That's called non-blocking.

[jasdfuwjass]

Doesn't this miss the forest for the trees? The entire point is to drive with epoll.

[LtdJorge]

Well, yes. But it means you can do sync non-blocking IO by hand.