Progress meter

libcurl can be made to output a progress meter on stderr. This feature isdisabled by default and is one of those options with an ones awkward negationin the name:CURLOPT_NOPROGRESS - set it to1L todisable progressmeter. Set it to0L 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, "https://curl.se/");    res = curl_easy_perform(curl);    curl_easy_cleanup(curl);  }  return (int)res;}