debug error

[fibonacci]

while compiling my php programme, i got a error message like this

Warning: Call-time pass-by-reference has been deprecated - argument passed by value; If you would like to pass it by reference, modify the declaration of array_walk(). If you would like to enable call-time pass-by-reference, you can set allow_call_time_pass_reference to true in your INI file. However, future versions may not support this any longer. in c:\program files\easyphp1-8\www\search\harvestclass.php on line 55

and below is my php code that generate those error message

<?php
require('dbclass.php');

class Harvest_Keywords {

var $_db;
var $_urlarray;
var $_stopwords = array ('and', 'but', 'are', 'the');
var $_allowwords = array ('c++', 'ado', 'vb');

function Harvest_Keywords($urls) {
    $this->_db = new DB_Class('test', 'username', 'password');
$this->_urlarray = trim ($urls);
$this->_urlarray = explode ("\n", $this->_urlarray);
}

function _prune (&$item, $key, $array) {
    $item = strtolower ($item);
    if (((preg_match ("/[^a-z0-9'\?!-]/", $item))
       || (strlen ($item) < 3)
       || (in_array($item, $this->_stopwords)))
       && (!in_array($item, $this->_allowwords))) {

         unset($array[$key]);
    } else {
        $item = addslashes(preg_replace("/[^a-z0-9'-]/i",
                                        '', $item));
    }
}

function _checkURL($url) {
    return preg_match ("/http:\/\/(.*)\.(.*)/i", $url);
}

function _getData($url) {
    $filehandle = @fopen($url, 'r');
    if(!$filehandle) {
        echo "Could not open URL ($url).<br />\n";
        $return = FALSE;
    } else {
        $data = fread($filehandle, 25000);
        fclose($filehandle);
        $data = strip_tags ($data);
        $data = str_replace('&nbsp;', ' ', $data);
        $return = $data;
    }
    return $return;
}

function _harvest($url) {
    if(!$this->_checkURL($url)) {
        echo "URL is not valid ($url).<br />\n";
    } elseif ($data = $this->_getData($url)) {
        $words = preg_split ("/[\s,.]+/", $data);
        array_walk ($words, array($this, '_prune'), &$words);
        sort ($words);
        $url_id = $this->_db->getone("SELECT id FROM urls "
                                     . "WHERE url='$url'");
        if($url_id) {
            $this->_db->query("DELETE FROM keywords "
                              . "WHERE url_id=$url_id");
        } else {
            $this->_db->query("INSERT INTO urls SET url='$url'");
            $url_id = mysql_insert_id();
        }
        $values = "($url_id, '$words[0]')";
        $numwords = count ($words);
        for ($i = 1; $i < $numwords; $i++) {
            $values .= ", ($url_id, '$words[$i]')";
        }
        $this->_db->query("INSERT INTO keywords VALUES $values");
    }
}

function process() {
    foreach($this->_urlarray as $url) {
        $this->_harvest($url);
    }
}
}
?> 

can anybody help me figure this things out...
thanks in advance...

[jazz_snob]

drop the & from &$words
actually, drop the & from infront of all your variables

[bogu]

The problem is here:

array_walk ($words, array($this, '_prune'), &$words);

u try to send pass a reference of array $word to your '_prune' method, why do u send it second time, u already have it there ...

array_walk ($words, array($this, '_prune'));

you already have the reference of $words array passed to this function

function _prune (&$item, $key) { 
        $item = strtolower ($item); 
        if (((preg_match ("/[^a-z0-9'\?!-]/", $item)) 
           || (strlen ($item) < 3) 
           || (in_array($item, $this->_stopwords))) 
           && (!in_array($item, $this->_allowwords))) { 

         unset($item[$key]); 
    } else { 
        $item = addslashes(preg_replace("/[^a-z0-9'-]/i", 
                                        '', $item)); 
    } 
}

P.S. BTW, very nice code ...