void curl_slist_free_all(struct curl_slist *list);
Passing in a NULL pointer in list will make this function return immediately with no action.
CURL *handle; struct curl_slist *slist=NULL; slist = curl_slist_append(slist, "X-libcurl: coolness"); if (slist == NULL) return -1; curl_easy_setopt(handle, CURLOPT_HTTPHEADER, slist); curl_easy_perform(handle); curl_slist_free_all(slist); /* free the list again */