Progress meter

libcurl can be made to output a progress meter on stderr. This feature is disabled by default and is one of those options with an ones awkward negation in the name: CURLOPT_NOPROGRESS - set it to 1L to disable progress meter. Set it to 0L to enable it.

Return error to stop transfer

It can look something like this in code:

#include <stdio.h>
#include <curl/curl.h>

int main(void)
  CURL *curl;
  CURLcode res = CURLE_OK;

  curl = curl_easy_init();
  if(curl) {
    /* enable progress meter */
    curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 0L);

    curl_easy_setopt(curl, CURLOPT_URL, "");

    res = curl_easy_perform(curl);


  return (int)res;