sleep_unless_lockfile (200, "$ENV{TEMP}\\lockfile");

sub sleep_unless_lockfile {
	my ($sleeptime, $lockfile)=@_;
	my $counter;
	{
	sleep 1;
	$counter++; print "$counter.";
	last if (-e $lockfile);
	last if $counter >= $sleeptime;
	redo;
	}
}