How to get errno when epoll_wait returns EPOLLERR?

Question

Is there a way to find out the errno when epoll_wait returns EPOLLERR for a particular fd?

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Answer 1

Just a minor point: Your test won't work correctly, for two reasons. If EPOLLERR is defined as, say, 0x8, then your test will be comparing 8 with one (since == has higher precedence than &), giving you a zero, then anding that with the event mask.

What you want is: (epoll_event.events & EPOLLERR) != 0 to test for the EPOLLERR bit being set.