curl_easy_perform program in C - c

Question

Now, after doing the changes in code I am able to send the POST resquest to SERVER and even server is sending the response. But now my program hangs at curl_easy_perform function. Do you have any idea?
curl -H "Authorization: Basic dGVzdENsaWVudDp0ZXN0U2VjcmV0" -X POST "http://x.x.x.x:8080/authservice/token?grant_type=client_credential"
My program:
struct url_data {
size_t size;
char* data;
};
static size_t write_data(char *buffer, size_t size, size_t nitems, void *userp)
{
struct url_data *data = (struct url_data *)userp;
size_t index = data->size;
size_t n = (size * nitems);
data->size += (size * nitems);
char* tmp = realloc(data->data, data->size + 1);
if(tmp) {
data->data = tmp;
} else {
if(data->data) free(data->data);
fprintf(stderr, "Failed to allocate memory.\n");
return EXIT_FAILURE;
}
memcpy(data->data + index, buffer, n);
data->data[data->size] = '\0';
return size * nitems;
}
int main(void)
{
int i = 0;
long http_code = 0;
CURL *curl;
CURLcode res;
struct curl_slist *slist=NULL;
struct url_data data;
data.size = 0;
data.data = (char*) malloc(4096); /* reasonable size initial buffer */
bzero(data.data, 4096);
//curl_global_init(CURL_GLOBAL_ALL);
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, "http://x.x.x.x:8080/authservice/token?grant_type=client_credential");
curl_easy_setopt(curl, CURLOPT_POST, 1L);
curl_easy_setopt(curl, CURLOPT_USERAGENT, "libcurl-agent/1.0");
curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &data);
curl_easy_setopt(curl, CURLOPT_TIMEOUT, 10);
slist = curl_slist_append(slist, "Authorization: Basic dGVzdENsaWVudDp0ZXN0U2VjcmV0");
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, slist);
slist = curl_slist_append(slist, "Content-Type:application/json");
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, slist);
slist = curl_slist_append(slist, "Content-Length: 0");
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, slist);
slist = curl_slist_append(slist, "Expect:");
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, slist);
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
res = curl_easy_perform(curl);
/* Check for errors */
if(res != CURLE_OK) {
fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
} else {
fprintf(stderr, "Data:[%s] Ret:[%s]\n", data.data, curl_easy_strerror(res));
}
res = curl_easy_getinfo (curl, CURLINFO_HTTP_CODE, &http_code);
printf("http_code:%ld\n", http_code);
/* always cleanup */
curl_easy_cleanup(curl);
if(data.data) free(data.data);
curl_slist_free_all(slist);
}
//curl_global_cleanup();
return 0;
}
Output:
* About to connect() to x.x.x.x port 8080 (#0)
* Trying x.x.x.x...
* connected
* Connected to x.x.x.x (x.x.x.x) port 8080 (#0)
> POST /authservice/token?grant_type=client_credential HTTP/1.1
User-Agent: libcurl-agent/1.0
Host: x.x.x.x:8080
Accept: */*
Authorization: Basic dGVzdENsaWVudDp0ZXN0U2VjcmV0
Content-Type:application/json
Content-Length: 0