descriptor multiplexing interfaces: epoll_wait (2), epoll_pwait (2), poll (2), ppoll (2), select ... been set. • epoll_wait (2), epoll_pwait (2). • semop (2), semtimedop (2). • sig…POSIX.1-2001 and later. See also : epoll_pwait (2), ppoll (2), pselect (2), sigaction (2), signalfd