Set the http referer header
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_REFERER, char *where);
Pass a pointer to a zero terminated string as parameter. It will be used to set the Referer: header in the http request sent to the remote server. This can be used to fool servers or scripts. You can also set any custom header with CURLOPT_HTTPHEADER(3).
If built with HTTP support
Returns CURLE_OK if HTTP support is enabled, CURLE_UNKNOWN_OPTION if not, or CURLE_OUT_OF_MEMORY if there was insufficient heap space.