Function nc::epoll_wait

pub fn epoll_wait(
    epfd: i32, 
    events: &mut [epoll_event_t], 
    max_events: i32, 
    timeout: i32
) -> Result<i32, Errno>

Wait for an I/O event on an epoll file descriptor.

let epfd = nc::epoll_create1(nc::EPOLL_CLOEXEC);
assert!(epfd.is_ok());
let epfd = epfd.unwrap();
let mut fds: [i32; 2] = [0, 0];
let ret = nc::pipe(&mut fds);
assert!(ret.is_ok());
let mut event = nc::epoll_event_t::default();
event.events = nc::EPOLLIN | nc::EPOLLET;
event.data.fd = fds[0];
let ctl_ret = nc::epoll_ctl(epfd, nc::EPOLL_CTL_ADD, fds[0], &mut event);
assert!(ctl_ret.is_ok());

let msg = "Hello, Rust";
let ret = nc::write(fds[1], msg.as_ptr() as usize, msg.len());
assert!(ret.is_ok());

let mut events = vec![nc::epoll_event_t::default(); 4];
let events_len = events.len();
let ret = nc::epoll_wait(epfd, &mut events, events_len as i32, 0);
assert!(ret.is_ok());
assert_eq!(ret, Ok(1));

for event in &events {
    // Ready to read
    if event.events == nc::EPOLLIN {
        let ready_fd = unsafe { event.data.fd };
        assert_eq!(ready_fd, fds[0]);
        let mut buf = vec![0_u8; 64];
        let buf_len = buf.len();
        let ret = nc::read(ready_fd, buf.as_mut_ptr() as usize, buf_len);
        assert!(ret.is_ok());
        let n_read = ret.unwrap() as usize;
        assert_eq!(msg.as_bytes(), &buf[..n_read]);
    }
}

assert!(nc::close(fds[0]).is_ok());
assert!(nc::close(fds[1]).is_ok());
assert!(nc::close(epfd).is_ok());