Ciao, e grazie !

Avrei risolto in questo modo:

codice:
function auth_clean_expired(){
    global $_CONFIG;
    global $conn;
    
    $result = mysqli_query($conn,"SELECT creation_date FROM ".$_CONFIG['table_sessioni']." WHERE uid='".auth_get_uid()."'");
    if($result){
        $data = $result->fetch_array(MYSQLI_ASSOC);
        if($data['creation_date']){
            if($data['creation_date'] + $_CONFIG['expire'] <= time()){
                switch(auth_get_option("TRANSICTION METHOD")){
                    case AUTH_USE_COOKIE:
                        setcookie('uid');
                    break;
                    case AUTH_USE_LINK:
                        global $_GET;
                        $_GET['uid'] = NULL;
                    break;
                }
            }
        }
    }
    
    mysqli_query($conn,"
    DELETE FROM ".$_CONFIG['table_sessioni']."
    WHERE creation_date + ".$_CONFIG['expire']." <= ".time()
    );
    
}
Inserito in ogni funzione.
A occhio e croce funziona, ma e' corretto ?