Use http post with form-data body to upload file to web server

http_post_form.c

#include <stdio.h>
#include <curl/curl.h>
int main(void)
{
  CURL *curl;
  CURLcode res;
 
  /* In windows, this will init the winsock stuff */ 
  curl_global_init(CURL_GLOBAL_ALL);
 
  /* get a curl handle */ 
  curl = curl_easy_init();
  if(curl) {
    /* First set the URL that is about to receive our POST. This URL can
       just as well be a https:// URL if that is what should receive the
       data. */ 
    curl_easy_setopt(curl, CURLOPT_URL, "http://localhost:8080");
    /* Now specify the POST data */ 
 
    struct curl_httppost* post = NULL;
    struct curl_httppost* last = NULL;

    curl_formadd(&post, &last, CURLFORM_COPYNAME, "name",
            CURLFORM_COPYCONTENTS, "value", CURLFORM_END);

    /* Add a single file */
    curl_formadd(&post, &last, CURLFORM_COPYNAME, "file",
            CURLFORM_FILE, "file.txt", CURLFORM_END);

    /* Set the form info */
    curl_easy_setopt(curl, CURLOPT_HTTPPOST, post);
    /* Perform the request, res will get the return code */ 
    res = curl_easy_perform(curl);
    /* Check for errors */ 
    if(res != CURLE_OK)
      fprintf(stderr, "curl_easy_perform() failed: %s\n",
              curl_easy_strerror(res));
 
    /* always cleanup */ 
    curl_easy_cleanup(curl);
    curl_formfree(post);
  }
  curl_global_cleanup();
  return 0;
}