function recuperer_page_cache($url, $delai=3600) {
   $cache = _DIR_CACHE.'url_'.md5($url);
   if (($GLOBALS['var_mode']
   OR !file_exists($cache)
   OR filemtime($cache)<time()-$delai
   )
   AND $contenu = recuperer_page($url))
       ecrire_fichier($cache, $contenu);
   lire_fichier($cache, $contenu);
   return $contenu;
}