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