Even more wrong php class autoload

more_wrong_php_autoload.php

<?php
function __autoload( $class_name )
{
    $file = $class_name . '.php';
    $dirs = array( 'lib1/', 'lib2/');

    foreach( $dirs as $dir )
    {
        if( file_exists($dir . $file) )
        {
            require_once $dir . $file;
            return;
        }
    }
}