Function nc::pselect6

pub fn pselect6(
    nfds: i32, 
    readfds: &mut fd_set_t, 
    writefds: &mut fd_set_t, 
    exceptfds: &mut fd_set_t, 
    timeout: &timespec_t, 
    sigmask: &sigset_t
) -> Result<i32, Errno>

Sychronous I/O multiplexing. Most architectures can't handle 7-argument syscalls. So we provide a 6-argument version where the sixth argument is a pointer to a structure which has a pointer to the sigset_t itself followed by a size_t containing the sigset size.