Calls epoll_ctl() using the current epoll file descriptor to modify the
registration of fd for events with fd as user data.
Creates the epoll_event_t instance passed to epoll_ctl() from events and
fd where data.fd is set to fd.
The current epoll file descriptor should have been sucessfully obtained
by create() or epoll_create1() and not already been closed, otherwise
epoll_ctl() will fail so that this method returns -1.
Calls epoll_ctl() using the current epoll file descriptor to modify the registration of fd for events with fd as user data.
Creates the epoll_event_t instance passed to epoll_ctl() from events and fd where data.fd is set to fd.
The current epoll file descriptor should have been sucessfully obtained by create() or epoll_create1() and not already been closed, otherwise epoll_ctl() will fail so that this method returns -1.