curl/docs/examples/httpcustomheader.c

/*****************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 */

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

int main(void)
{
  CURL *curl;
  CURLcode res;

  curl = curl_easy_init();
  if(curl) {
    struct curl_slist *chunk = NULL;

    chunk = curl_slist_append(chunk, "Accept: moo");
    chunk = curl_slist_append(chunk, "Another: yes");

    /* request with the built-in Accept: */
    curl_easy_setopt(curl, CURLOPT_URL, "localhost");
    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
    res = curl_easy_perform(curl);

    /* redo request with our own custom Accept: */
    res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
    res = curl_easy_perform(curl);

    /* always cleanup */
    curl_easy_cleanup(curl);
  }
  return 0;
}