NAME

       CURLOPT_SSL_ENABLE_ALPN - Application Layer Protocol Negotiation

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_ENABLE_ALPN, long npn);

DESCRIPTION

       Pass  a  long  as  parameter,  0 or 1 where 1 is for enable and 0 for disable. This option
       enables/disables ALPN in the SSL handshake (if the SSL backend libcurl  is  built  to  use
       supports it), which can be used to negotiate http2.

DEFAULT

       1, enabled

PROTOCOLS

       HTTP

EXAMPLE

       CURL *curl = curl_easy_init();
       if(curl) {
         curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
         curl_easy_setopt(curl, CURLOPT_SSL_ENABLE_ALPN, 0L);
         ret = curl_easy_perform(curl);
         curl_easy_cleanup(curl);
       }

AVAILABILITY

       Added in 7.36.0

RETURN VALUE

       Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

SEE ALSO

       CURLOPT_SSL_ENABLE_NPN(3), CURLOPT_SSL_OPTIONS(3),