Use with [curl->set] to set type of the proxy.

Available options for this are CURLPROXY_HTTP, CURLPROXY_HTTP_1_0, CURLPROXY_SOCKS4, CURLPROXY_SOCKS5, CURLPROXY_SOCKS4A and CURLPROXY_SOCKS5_HOSTNAME. The HTTP type is default.

If you set CURLOPT_PROXYTYPE to CURLPROXY_HTTP_1_0, it will only affect how libcurl speaks to a proxy when CONNECT is used. The HTTP version used for "regular" HTTP requests is instead controlled with CURLOPT_HTTP_VERSION.