epoll_ctl(2) System Calls Manual epoll_ctl(2) epoll_ctl - epoll (libc -lc) #include int epoll_ctl(int epfd, int op, int fd, struct epoll_event *_Nullable event); epoll(7) epfd. op fd. op : EPOLL_CTL_ADD epoll epfd. fd ( epoll(7) open(2)) event. EPOLL_CTL_MOD fd event. EPOLL_CTL_DEL ( ) fd . event NULL ( ). event fd. struct epoll_event epoll_event(3type). data epoll_event ( epoll_wait(2)) . events epoll_event ( epoll_wait(2)) . : EPOLLIN read(2). EPOLLOUT write(2). EPOLLRDHUP ( Linux 2.6.17) . ( .) EPOLLPRI . POLLPRI poll(2). EPOLLERR . . epoll_wait(2) events epoll_ctl(). EPOLLHUP (Hang up) . epoll_wait(2) events epoll_ctl(). . 0 ( ) . : EPOLLET . epoll . epoll(7) . EPOLLONESHOT ( Linux 2.6.2) . epoll_wait(2) epoll. epoll_ctl() EPOLL_CTL_MOD . EPOLLWAKEUP ( Linux 3.5) EPOLLONESHOT EPOLLET CAP_BLOCK_SUSPEND "" "" . "" epoll_wait(2) epoll_wait(2) epoll(7) EPOLL_CTL_DEL EPOLLWAKEUP EPOLL_CTL_MOD. . EPOLLEXCLUSIVE ( Linux 4.5) epoll fd. epoll EPOLLEXCLUSIVE epoll epoll_wait(2). ( EPOLLEXCLUSIVE) epoll . EPOLLEXCLUSIVE . epoll EPOLLEXCLUSIVE epoll EPOLLEXCLUSIVE epoll EPOLLEXCLUSIVE. EPOLLEXCLUSIVE: EPOLLIN EPOLLOUT EPOLLWAKEUP EPOLLET. EPOLLHUP EPOLLERR : events. events EINVAL. EPOLLEXCLUSIVE EPOLL_CTL_ADD EPOLL_CTL_MOD . EPOLLEXCLUSIVE epoll_ctl() EPOLL_CTL_MOD epfd, fd . epoll_ctl() EPOLLEXCLUSIVE events fd epoll. EINVAL. epoll_ctl() . epoll_ctl() -1 errno . EBADF epfd fd . EEXIST op EPOLL_CTL_ADD fd epoll . EINVAL epfd epoll fd epfd op . EINVAL EPOLLEXCLUSIVE events. EINVAL op EPOLL_CTL_MOD events EPOLLEXCLUSIVE. EINVAL op EPOLL_CTL_MOD EPOLLEXCLUSIVE epfd, fd. EINVAL EPOLLEXCLUSIVE event fd epoll. ELOOP fd epoll EPOLL_CTL_ADD epoll epoll 5. ENOENT op EPOLL_CTL_MOD EPOLL_CTL_DEL fd epoll . ENOMEM op . ENOSPC /proc/sys/fs/epoll/max_user_watches (EPOLL_CTL_ADD) epoll. epoll(7) . EPERM fd epoll. fd . . 2.6 glibc 2.3.2. epoll poll(2). 2.6.9 EPOLL_CTL_DEL event . 2.6.9 event NULL EPOLL_CTL_DEL. 2.6.9 event. EPOLLWAKEUP flags CAP_BLOCK_SUSPEND EPOLLWAKEUP . flags EPOLLWAKEUP CAP_BLOCK_SUSPEND ( ). CAP_BLOCK_SUSPEND EPOLLWAKEUP. epoll_create(2) epoll_wait(2) ioctl_eventpoll(2) poll(2) epoll(7) 3 . . : . 6.18 25 2025 epoll_ctl(2)