使用libcurl在PUT请求中发送字符串

My code looks like this:

我的代码如下所示：

curl = curl_easy_init();

if (curl) {
    headers = curl_slist_append(headers, client_id_header);
    headers = curl_slist_append(headers, "Content-Type: application/json");

    curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers); 
    curl_easy_setopt(curl, CURLOPT_URL, "127.0.0.1/test.php");  
    curl_easy_setopt(curl, CURLOPT_PUT, 1L);

    res = curl_easy_perform(curl);
    res = curl_easy_send(curl, json_struct, strlen(json_struct), &io_len);

    curl_slist_free_all(headers);
    curl_easy_cleanup(curl);
}
curl = c