Function epoll_wait 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn epoll_wait(
    epfd: c_int,
    events: *mut epoll_event,
    maxevents: c_int,
    timeout: c_int,
) -> c_int

Non-POSIX, see https://man7.org/linux/man-pages/man2/epoll_wait.2.html.

Waits for events on the epoll instance referred to by the file descriptor epdf.

timeout represents the number of milliseconds this function call will block.

Will block until either:

• a file descriptor delivers an event
• the call is interrupted by a signal handler
• the timeout expires

A timeout of -1 will block indefinitely. A timeout of 0 will return immediately, even if no events are available.

Upon success, returns the number of file descriptors ready for the requested I/O operation, or 0 if no file descriptor became ready during the requested timeout. Upon failure, returns -1 and sets errno to indicate the error.