用PHP访问云oss图片服务器时，提示找不到这个常量。常量要定义成什么？

Notice : Use of undefined constant CURLOPT_CLOSEPOLICY - assumed 'CURLOPT_CLOSEPOLICY' in





public function prep_request()
    {
        $curl_handle = curl_init();


        // Set default options.
        curl_setopt($curl_handle, CURLOPT_URL, $this->request_url);
        curl_setopt($curl_handle, CURLOPT_FILETIME, true);
        curl_setopt($curl_handle, CURLOPT_FRESH_CONNECT, false);
        curl_setopt($curl_handle, CURLOPT_CLOSEPOLICY, CURLCLOSEPOLICY_LEAST_RECENTLY_USED);//就这两个东西？ 我找了PHP最新的代码库没看到这个东西呀。
        curl_setopt($curl_handle, CURLOPT_MAXREDIRS, 5);
        curl_setopt($curl_handle, CURLOPT_HEADER, true);
        curl_setopt($curl_handle, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($curl_handle, CURLOPT_TIMEOUT, 5184000);
        curl_setopt($curl_handle, CURLOPT_CONNECTTIMEOUT, 120);
        curl_setopt($curl_handle, CURLOPT_NOSIGNAL, true);
        curl_setopt($curl_handle, CURLOPT_REFERER, $this->request_url);
        curl_setopt($curl_handle, CURLOPT_USERAGENT, $this->useragent);
        curl_setopt($curl_handle, CURLOPT_READFUNCTION, array($this, 'streaming_read_callback'));