Make asynchronous http request in C - c

Question

hi I'm a noobie with pthread and http requests in C, but I wanted to know if there is a way to make multiple asynchronous http calls in C, possibly at the same time. I ask "at the same time" because having a list of about 200-300 urls I wanted to parallelize requests by working on multiple threads (since asynchronous work on only one thread) passing sublists to threads and getting responses as fast as possible, avoiding bottleneck. I haven't found much for C looking on the internet, I only found curl_multi_* but i didn't quite understand how to use it. Thus I thought about writing something like this but it doesn't seem to solve the problem. Does anyone have any tips? or good tutorial for this stuff in C?
void *make_req(void *arguments) {
CURL *curl;
CURLcode res;
memory_t chunk;
data_t * data = (data_t*)arguments;
static int i = -1;
chunk.response = malloc(1);
chunk.size = 0;
curl = curl_easy_init();
while (i < data->nbr_sub_match) {
pthread_mutex_lock(&lock);
i++;
pthread_mutex_unlock(&lock);
curl_easy_setopt(curl, CURLOPT_BUFFERSIZE, 1<<23);
// curl_easy_setopt(curl, CURLOPT_ACCEPT_ENCODING, "gzip, deflate");
curl_easy_setopt(curl, CURLOPT_TCP_FASTOPEN, 1L);
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, data->header);
curl_easy_setopt(curl, CURLOPT_URL, data->sub_match_urls[i]);
curl_easy_setopt(curl, CURLOPT_TCP_NODELAY, 1L);
/* send all data to this function */
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, cb);
/* we pass our 'chunk' struct to the callback function */
curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&chunk);
curl_easy_setopt(curl, CURLOPT_USERAGENT, "libcurl-agent/1.0");
/* get it! */
res = curl_easy_perform(curl);
/* check for errors */
if(res != CURLE_OK) {
fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
}
pthread_mutex_lock(&lock);
data->sub_match_json[data->response_counter++] = chunk.response;
pthread_mutex_unlock(&lock);
}
/* cleanup curl stuff */
curl_easy_cleanup(curl);
i = -1;
// return chunk.response;
return NULL;
}
void start_threads(data_t *data) {
int err, i = 0;
pthread_t thread[data->nbr_threads];
curl_global_init(CURL_GLOBAL_ALL);
if(pthread_mutex_init(&lock, NULL) != 0)
fprintf(stderr, "failed to initialize mutex: %s\n", strerror(errno));
while (i < data->nbr_threads) {
err = pthread_create(&thread[i], NULL, make_req, (void *)data);
if (err != 0)
{
fprintf(stderr, "Error: impossible make new thread %s\n", strerror(errno));
exit(1);
}
i++;
}
// pthread_mutex_destroy(&lock);
while (--i >= 0) {
pthread_join(thread[i], NULL);
}
curl_global_cleanup();
}