pause - stop until signal
Pause never returns normally. It is used to give up control while
waiting for a signal from kill(2) or an interval timer, see
setitimer(2). Upon termination of a signal handler started during
a pause, the pause call will return.
Always returns -1.
Pause always returns:
[EINTR] The call was interrupted.
kill(2), select(2), sigpause(2)