CURLOPT_HTTP_VERSION(3)    curl_easy_setopt options    CURLOPT_HTTP_VERSION(3)

NAME
       CURLOPT_HTTP_VERSION - specify HTTP protocol version to use

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HTTP_VERSION, long ver-
       sion);

DESCRIPTION
       Pass version a long, set to one of the values described below. They ask
       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.

       Note that the HTTP version is just a request. libcurl will still prior-
       itize to re-use an existing connection so it might then re-use  a  con-
       nection using a HTTP version you haven't asked for.

       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  1.1  if
              HTTP 2 can't be negotiated with the server. (Added in 7.33.0)

              The  alias  CURL_HTTP_VERSION_2  was  added  in 7.43.0 to better
              reflect the actual protocol name.

       CURL_HTTP_VERSION_2TLS
              Attempt HTTP 2 over TLS (HTTPS) only. libcurl will fall back  to
              HTTP  1.1  if  HTTP 2 can't be negotiated with the HTTPS server.
              For clear text HTTP servers, libcurl will  use  1.1.  (Added  in
              7.47.0)

       CURL_HTTP_VERSION_2_PRIOR_KNOWLEDGE
              Issue  non-TLS  HTTP  requests  using  HTTP/2  without  HTTP/1.1
              Upgrade. It requires prior knowledge that  the  server  supports
              HTTP/2  straight  away.  HTTPS requests will still do HTTP/2 the
              standard way with negotiated protocol version in the  TLS  hand-
              shake. (Added in 7.49.0)

DEFAULT
       CURL_HTTP_VERSION_NONE

PROTOCOLS
       HTTP

EXAMPLE
       TODO

AVAILABILITY
       Along with HTTP

RETURN VALUE
       Returns CURLE_OK if HTTP is supported, and CURLE_UNKNOWN_OPTION if not.

SEE ALSO
       CURLOPT_SSLVERSION(3), CURLOPT_HTTP200ALIASES(3),

libcurl 7.54.0                   May 01, 2016          CURLOPT_HTTP_VERSION(3)