how to generate random non repeated numbers in php

[tony007]

You could use the time that it was generated on by using time() (http://uk2.php.net/manual/en/function.time.php)

$filename = time() . ".txt";
$handle = fopen ($filename,"w+"); 

many thanks for u reply. the whole idea of doing this is to generate unique file for each request from user .Do think by using this method no 2 user get same .txt file when they execute this page?Thanks