Do I need to manually EPOLL_CTL_DEL the event after only a EPOLLONESHOT event has been triggered when closing the socket?

Question

struct epoll_event ev, events[20];
ev.events = EPOLLOUT | EPOLLONESHOT;
ev.data.sock = some_socket;
epoll_ctl(epfd, EPOLL_CTL_ADD, some_socket, &ev);
// then the EPOLLOUT event has triggered by epoll_wait
epoll_ctl(epfd, EPOLL_CTL_DEL, some_socket, NULL); // should it be called? will it cause error?

after the EPOLLOUT event has been triggered, the MAN page said the event has now been disabled and will not triggered. I don't know if it's completely same as EPOLL_CTL_DEL. Do I need to manually call EPOLL_CTL_DEL when closing the socket if EPOLLOUT | EPOLLONESHOT is the only event that has been triggered?

score 0 · Answer 1 · answered Jul 13 '23 at 18:38

"When closing the socket" implies you do not need epoll_ctl with EPOLL_CTL_DEL unless there other fine moments. Did you duplicate the fd? No? Then you don't need to. Yes? May depend on the program logic: whether or not you need that socket to close now or it is still monitored. For details please read here: Epoll: does it silently remove fds?

Do I need to manually EPOLL_CTL_DEL the event after only a EPOLLONESHOT event has been triggered when closing the socket?

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