# Unlike with python, the ioctl needs to be hard-coded.
# FIONREAD == 0x4004667 should be true of macOS.
# On the other hand, Perl startup time is lower than Python.
perl -MIO::Select -e '
	my $s = IO::Select->new(\*STDIN);
	if ($s->can_read(0.5)) {
		ioctl(STDIN, 0x4004667f, $buf = pack("L", 0)) or exit 2;
		exit !unpack("L", $buf);
	}
	exit 1;
'