my $time_out = 5;
my $flag = 1;
while(1){
	my $diff = time() - $starttime;
	if($diff >= $time_out){
		print "already reached maximum timeout\n";
		last;
	}
	if($flag){
		printData();
		$flag = 0;
	}
	sleep(1);
}
sub printData {
	print "i am running....\n";
}