sub _has_flags {
	my $check_flag = _names_to_flags(@_);
	return sub {
		my ($fh, $layer) = @_;
		my $iterator = natatime(3, PerlIO::get_layers($fh, details => 1));
		while (my ($name, $arguments, $flags) = $iterator->()) {
			next if defined $layer and $name ne $layer;
            print('FL='.unpack('H8',pack('N',$flags)).','.unpack('B32',pack('N',$flags))."\n");
            print('CK='.unpack('H8',pack('N',$check_flag)).','.unpack('B32',pack('N',$check_flag))."\n");
			my $entry = $flags & $check_flag;
			return 1 if $entry;
		}
		return 0;
	}
}