CURL *curl = curl_easy_init();
if(curl) {
  CURLcode ret;
  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
  /* allow whatever auth the server speaks */
  curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
  curl_easy_setopt(curl, CURLOPT_USERPWD, "james:bond");
  ret = curl_easy_perform(curl);
}