gistfile1.c

CURLM *curl;

static void foo_cb(const char *data, const char *moredata) {
    struct curl_httppost *post = NULL;
    struct curl_httppost *last = NULL;
    
    CURL *handle;
    handle = curl_easy_init();
  
    curl_formadd(&post, &last,
	         CURLFORM_COPYNAME, "data",
	         CURLFORM_COPYCONTENTS, data,
	         CURLFORM_END);

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

    curl_easy_setopt(handle, CURLOPT_HTTPPOST, post);

    curl_multi_add_handle(curl, handle);

    curl_formfree(post);
}

static void plugin_load() {
    /* pseudocode */
    signal_connect('foo-signal', foo_cb);
    curl = curl_multi_init();
}