src/Skeetr/Runtime/Overrides/Session.php
final public static function session_start()
    {
        if ( self::$started ) trigger_error('Session already started', E_USER_WARNING);

        self::$started = true;

        if ( isset($_COOKIE[session_name()]) ) {
            self::$id = $_COOKIE[session_name()];
        } else {
            self::$id = uniqid();

            $config = self::session_get_cookie_params();
            Cookie::setcookie(
                session_name(), self::$id,
                $config['lifetime'], $config['path'], $config['domain'],
                $config['secure'], $config['httponly']
            );
        }

        if ( !$savePath = session_save_path() ) $savePath = sys_get_temp_dir();
        if ( !is_dir($savePath) ) mkdir($savePath, 0777);

        self::$file = sprintf('%s/sess_%s', $savePath, self::$id);

        if (self::$handler) {
            self::$handler->open($savePath, session_name());
            self::$handler->read(self::$id);
        }

        if ( file_exists(self::$file) ) {
            $data = file_get_contents(self::$file);
            session_decode($data);
        }

        return true;
    }
final public static function session_start()
    {
        if ( self::$started ) trigger_error('Session already started', E_USER_WARNING);

        self::$started = true;

        if ( isset($_COOKIE[session_name()]) ) {
            self::$id = $_COOKIE[session_name()];
        } else {
            self::$id = uniqid();

            $config = self::session_get_cookie_params();
            Cookie::setcookie(
                session_name(), self::$id,
                $config['lifetime'], $config['path'], $config['domain'],
                $config['secure'], $config['httponly']
            );
        }

        if ( !$savePath = session_save_path() ) $savePath = sys_get_temp_dir();
        if ( !is_dir($savePath) ) mkdir($savePath, 0777);

        self::$file = sprintf('%s/sess_%s', $savePath, self::$id);

        if (self::$handler) {
            self::$handler->open($savePath, session_name());
            self::$handler->read(self::$id);
        }

        if ( file_exists(self::$file) ) {
            $data = file_get_contents(self::$file);
            session_decode($data);
        }

        return true;
    }
Start new or resume existing session

@link http://www.php.net/manual/en/function.session-start.php