Function pselect6 

pub fn pselect6(
    nfds: usize,
    readfds: usize,
    writefds: usize,
    exceptfds: usize,
    timeout: usize,
    _sigmask: usize,
) -> isize

pselect6 - synchronous I/O multiplexing with signal mask Note: sigmask handling requires signal subsystem refactoring, currently ignored