use Socket qw( AF_UNIX SOCK_STREAM PF_UNSPEC );

sub _pipe {
    socketpair($_[0], $_[1], AF_UNIX, SOCK_STREAM, PF_UNSPEC)
        or return undef;
    shutdown($_[0], 1);  # No more writing for reader
    shutdown($_[1], 0);  # No more reading for writer
    return 1;
}