phpcms如何配置404

<?php header(&#39;http/1.1 404 Not found&#39;);  ?>

<?php header( $_SERVER[&#39;SERVER_PROTOCOL&#39;]." 404 Not Found", true, 404 );  ?>

<?php  header( $_ENV[&#39;SERVER_PROTOCOL&#39;]." 404 Not Found", true, 404 );  ?>

function page404(){  
    header($_SERVER['SERVER_PROTOCOL']." 404 Not Found", true, 404 );  
    require('page404.php');  
    exit();  
}

if(!$catid || !$id)   
        page404()
if(!isset($CATEGORYS[$catid]) || $CATEGORYS[$catid]['type']!=0)  
       page404()
if(!$r || $r['status'] != 99)   
       page404()

if(!isset($CATEGORYS[$catid])) 
page404()