linuxepoll

How do we know whether call to epoll_wait() is edge triggered or level triggered?

I know that specifying the event EPOLLETswitches epoll from being level-triggered to edge-triggered. Does it mean by default call to epoll_wait() is Level-Triggered?

Solution

  • See http://man7.org/linux/man-pages/man7/epoll.7.html

    By contrast, when used as a level-triggered interface (the default,
when EPOLLET is not specified), epoll is simply a faster poll(2), and
can be used wherever the latter is used since it shares the same
semantics.

    So, when EPOLLET is not specified, level-triggered is the default option.