CURLOPT_FORBID_REUSE man page
CURLOPT_FORBID_REUSE — make connection get closed at once after use
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_FORBID_REUSE, long close);
Pass a long. Set close to 1 to make libcurl explicitly close the connection when done with the transfer. Normally, libcurl keeps all connections alive when done with one transfer in case a succeeding one follows that can re-use them. This option should be used with caution and only if you understand what it does as it can seriously impact performance.
Set to 0 to have libcurl keep the connection open for possible later re-use (default behavior).
curl_easy_setopt(3), CURLOPT_FRESH_CONNECT(3), CURLOPT_PIPEWAIT(3), CURLOPT_URL(3), libcurl-tutorial(3).