function query(/* $sql [, ... ] */)
    {
        // SQL statement
        $sql = func_get_arg(0);

	// parameters, if any
        $parameters = array_slice(func_get_args(), 1);

	// try to connect to database
        static $handle;
        if (!isset($handle))
        {
            try
            {
                // connect to database
                $handle =  new PDO("mysql:dbname=" . DATABASE . ";host=" . SERVER . ";charset=utf8", USERNAME, PASSWORD);
                // ensure that PDO::prepare returns false when passed invalid SQL
                $handle->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
            }
            catch (Exception $e)
            {
                // trigger (big, orange) error
                trigger_error($e->getMessage(), E_USER_ERROR);
                exit;
            }
        }

        // prepare SQL statement
        $statement = $handle->prepare($sql);
        if ($statement === false)
        {
            // trigger (big, orange) error
            trigger_error($handle->errorInfo()[2], E_USER_ERROR);
            exit;
        }
        // execute SQL statement
        $results = $statement->execute($parameters);
        // return result set's rows, if any
        if ($results !== false)
        {
            return $statement->fetchAll(PDO::FETCH_ASSOC);
        }
        else
        {
            return false;
        }
    }