Ciao.
Provata questo codice con

magic_quotes_gpc = On


Codice PHP:
<?php
if(filter_has_var(INPUT_POST, 'action')){
    $options= array("options"=>array("regexp"=>'#^[a-zA-Z0-9_\-\']+$#'));
    $name= filter_input(INPUT_POST,'name',FILTER_VALIDATE_REGEXP,$options);
    $surname= filter_input(INPUT_POST,'name',FILTER_VALIDATE_REGEXP,$options);
    echo 'Name '.$name;
    echo '
';
    echo '<pre>';
    var_dump($_POST);    
}


?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
    <meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />
    <meta name="author" content="www.serials.ws" />

    <title>Magic quote</title>
</head>

<body>



</body>
</html>
<div id="content">
<form action="" method="post">
<input type="text" name="name" value="" />

<input name="action" type="hidden" value="insert" />
<input type="submit" name="user_insert" value="Insert" />
</form>
</div>