CURLOPT_HTTP_VERSION − specify HTTP protocol version to use
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HTTP_VERSION, long version);
Pass version a long, set to one of the values described below. They force libcurl to use the specific HTTP versions. This is not sensible to do unless you have a good reason. You have to set this option if you want to use libcurl’s HTTP/2 support.
CURL_HTTP_VERSION_NONE
We don’t care about what version the library uses. libcurl will use whatever it thinks fit.
CURL_HTTP_VERSION_1_0
Enforce HTTP 1.0 requests.
CURL_HTTP_VERSION_1_1
Enforce HTTP 1.1 requests.
CURL_HTTP_VERSION_2_0
Attempt HTTP 2 requests. libcurl will fall back to HTTP 1.x if HTTP 2 can’t be negotiated with the server. (Added in 7.33.0)
CURL_HTTP_VERSION_NONE
HTTP
TODO
Along with HTTP
Returns CURLE_OK if HTTP is supported, and CURLE_UNKNOWN_OPTION if not.