nc 0.9.8

Access system calls directly
Documentation 
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/// Examine and change a signal action.
///
/// # Examples
///
/// ```
/// fn handle_sigterm(sig: i32) {
///     assert_eq!(sig, nc::SIGTERM);
/// }
///
/// let sa = nc::new_sigaction(handle_sigterm);
/// let ret = unsafe { nc::rt_sigaction(nc::SIGTERM, Some(&sa), None) };
/// let ret = unsafe { nc::kill(nc::getpid(), nc::SIGTERM) };
/// assert!(ret.is_ok());
/// ```
pub unsafe fn rt_sigaction(
    sig: i32,
    act: Option<&sigaction_t>,
    old_act: Option<&mut sigaction_t>,
) -> Result<(), Errno> {
    let sig = sig as usize;
    let act_ptr = act.map_or(core::ptr::null::<sigaction_t>() as usize, |act| {
        core::ptr::from_ref(act) as usize
    });
    let old_act_ptr = old_act.map_or(core::ptr::null_mut::<sigaction_t>() as usize, |old_act| {
        core::ptr::from_mut(old_act) as usize
    });
    let sigset_size = core::mem::size_of::<sigset_t>();
    unsafe { syscall4(SYS_RT_SIGACTION, sig, act_ptr, old_act_ptr, sigset_size).map(drop) }
}