C libcurl verify if message is sent to webhook - c

Question

Because of variable my_description changes frequently I get this error:
{"code": 50109, "message": "The request body contains invalid JSON."}
It is possible to modify the code below to verify if libcurl gets an error when sending the message to webhook? I want to print when the message is sent and when exist an error in sending a message.
I tried this:
if(res != CURLE_OK)
fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
but it is not helpful.
Anybody can help me, please? Thanks!
#include <stdio.h>
#include <curl/curl.h>
#define nullptr ((void*)0)
int main() {
char message[65500];
int max_len = sizeof message;
CURL *curl;
CURLcode res;
char webhook[] = "DISCORD_WEBHOOK";
char my_description[] = "Description";
snprintf(message, max_len,"{\"username\": \"Test\",\"embeds\":[{\"description\": \"%s\"}]}", my_description);
curl = curl_easy_init();
if(curl) {
struct curl_slist* headers = nullptr;
headers = curl_slist_append(headers, "Content-Type: application/json");
curl_easy_setopt(curl, CURLOPT_URL, webhook);
curl_easy_setopt(curl, CURLOPT_POSTFIELDS, message);
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
return 0;
}

Answer 1

I tried this:
if(res != CURLE_OK)
fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
You might want to try this:
if(res != CURLE_OK) {
fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
} else {
long response_code = 0;
curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &response_code);
if(response_code != 200) {
// Error
}
}
An invalid JSON can be caused by quotes in my_description. Quotes must be replaced with escape sequences \".