In php with the function curl_init ();
$handle = curl_init($url);
curl_setopt($handle, CURLOPT_RETURNTRANSFER, TRUE);
/* Obtendo o arquivo que está conectado a $url. */
$response = curl_exec($handle);
/* Checando se há erro 404 (Arquivo não existe). */
$httpCode = curl_getinfo($handle, CURLINFO_HTTP_CODE);
if($httpCode == 404) {
/* Aqui está a resposta do erro 404. */
}
curl_close($handle);
/* $response aqui. */
Unmanaged Site Via .htacess: :
ErrorDocument 404 /404.html
Joomla:
if (($this->error->getCode()) == '404') {
header('Location: /index.php?option=com_content&view=article&id=75');
exit;
}
Wordpress:
<?php
/**
* The template for displaying 404 pages (Not Found)
*
* @package WordPress
* @subpackage Twenty_Thirteen
* @since Twenty Thirteen 1.0
*/
get_header(); ?>
<div id="primary" class="content-area">
<div id="content" class="site-content" role="main">
<header class="page-header">
<h1 class="page-title"><?php _e( 'Not Found', 'twentythirteen' ); ?></h1>
</header>
<div class="page-wrapper">
<div class="page-content">
<h2><?php _e( 'This is somewhat embarrassing, isn’t it?', 'twentythirteen' ); ?></h2>
<p><?php _e( 'It looks like nothing was found at this location. Maybe try a search?', 'twentythirteen' ); ?></p>
<?php get_search_form(); ?>
</div><!-- .page-content -->
</div><!-- .page-wrapper -->
</div><!-- #content -->
</div><!-- #primary -->
<?php get_footer(); ?>