1---
2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
3SPDX-License-Identifier: curl
4Title: CURLOPT_SSL_ENABLE_NPN
5Section: 3
6Source: libcurl
7See-also:
8  - CURLOPT_SSL_ENABLE_ALPN (3)
9  - CURLOPT_SSL_OPTIONS (3)
10Protocol:
11  - TLS
12TLS-backend:
13  - All
14Added-in: 7.36.0
15---
16
17# NAME
18
19CURLOPT_SSL_ENABLE_NPN - use NPN
20
21# SYNOPSIS
22
23~~~c
24#include <curl/curl.h>
25
26CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_ENABLE_NPN, long npn);
27~~~
28
29# DESCRIPTION
30
31Deprecated since 7.86.0. Setting this option has no function.
32
33Pass a long as parameter, 0 or 1 where 1 is for enable and 0 for disable. This
34option enables/disables NPN in the SSL handshake (if the SSL backend libcurl
35is built to use supports it), which can be used to negotiate http2.
36
37# DEFAULT
38
391, enabled
40
41# %PROTOCOLS%
42
43# EXAMPLE
44
45~~~c
46int main(void)
47{
48  CURL *curl = curl_easy_init();
49  if(curl) {
50    CURLcode res;
51    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
52    curl_easy_setopt(curl, CURLOPT_SSL_ENABLE_NPN, 1L);
53    res = curl_easy_perform(curl);
54    curl_easy_cleanup(curl);
55  }
56}
57~~~
58
59# DEPRECATED
60
61Deprecated since 7.86.0.
62
63# %AVAILABILITY%
64
65# RETURN VALUE
66
67Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
68