Function nc::setitimer

pub fn setitimer(
    which: i32, 
    new_val: &itimerval_t, 
    old_val: &mut itimerval_t
) -> Result<(), Errno>

Set value of an interval timer.

use core::mem::size_of;

fn handle_alarm(signum: i32) {
    assert_eq!(signum, nc::SIGALRM);
    let msg = "Hello alarm";
    let _ = nc::write(2, msg.as_ptr() as usize, msg.len());
}

let sa = nc::sigaction_t {
    sa_handler: handle_alarm as nc::sighandler_t,
    sa_flags: 0,
    ..nc::sigaction_t::default()
};
let mut old_sa = nc::sigaction_t::default();
let ret = nc::rt_sigaction(nc::SIGALRM, &sa, &mut old_sa, size_of::<nc::sigset_t>());
assert!(ret.is_ok());

// Single shot timer, actived after 1 second.
let itv = nc::itimerval_t {
    it_value: nc::timeval_t {
        tv_sec: 1,
        tv_usec: 0,
    },
    it_interval: nc::timeval_t {
        tv_sec: 0,
        tv_usec: 0,
    },
};
let mut prev_itv = nc::itimerval_t::default();
let ret = nc::setitimer(nc::ITIMER_REAL, &itv, &mut prev_itv);
assert!(ret.is_ok());

let ret = nc::getitimer(nc::ITIMER_REAL, &mut prev_itv);
assert!(ret.is_ok());
assert!(prev_itv.it_value.tv_sec <= itv.it_value.tv_sec);

let ret = nc::pause();
assert_eq!(ret, Err(nc::EINTR));

let ret = nc::getitimer(nc::ITIMER_REAL, &mut prev_itv);
assert!(ret.is_ok());
assert_eq!(prev_itv.it_value.tv_sec, 0);
assert_eq!(prev_itv.it_value.tv_usec, 0);