curl/docs/libcurl/opts/CURLOPT_SSL_ENABLE_NPN.3

.\" **************************************************************************
.\" *                                  _   _ ____  _
.\" *  Project                     ___| | | |  _ \| |
.\" *                             / __| | | | |_) | |
.\" *                            | (__| |_| |  _ <| |___
.\" *                             \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
.\" *
.\" * This software is licensed as described in the file COPYING, which
.\" * you should have received as part of this distribution. The terms
.\" * are also available at https://curl.se/docs/copyright.html.
.\" *
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
.\" * copies of the Software, and permit persons to whom the Software is
.\" * furnished to do so, under the terms of the COPYING file.
.\" *
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
.\" * KIND, either express or implied.
.\" *
.\" **************************************************************************
.\"
.TH CURLOPT_SSL_ENABLE_NPN 3 "19 Jun 2014" "libcurl 7.37.0" "curl_easy_setopt options"
.SH NAME
CURLOPT_SSL_ENABLE_NPN \- enable NPN
.SH SYNOPSIS
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_ENABLE_NPN, long npn);
.SH DESCRIPTION
Pass a long as parameter, 0 or 1 where 1 is for enable and 0 for disable. This
option enables/disables NPN in the SSL handshake (if the SSL backend libcurl
is built to use supports it), which can be used to negotiate http2.
.SH DEFAULT
1, enabled
.SH PROTOCOLS
HTTP
.SH EXAMPLE
.nf
CURL *curl = curl_easy_init();
if(curl) {
  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
  curl_easy_setopt(curl, CURLOPT_SSL_ENABLE_NPN, 1L);
  ret = curl_easy_perform(curl);
  curl_easy_cleanup(curl);
}
.fi
.SH AVAILABILITY
Added in 7.36.0
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH "SEE ALSO"
.BR CURLOPT_SSL_ENABLE_ALPN "(3), " CURLOPT_SSL_OPTIONS "(3), "