curl/docs/libcurl/opts/CURLOPT_SSL_ENABLE_ALPN.md
Daniel Stenberg b935fd4a07
docs: make each libcurl man specify protocol(s)
The mandatory header now has a mandatory list of protocols for which the
manpage is relevant.

Most man pages already has a "PROTOCOLS" section, but this introduces a
stricter way to specify the relevant protocols.

cd2nroff verifies that at least one protocol is mentioned (which can be
`*`).

This information is not used just yet, but A) the PROTOCOLS section can
now instead get generated and get a unified wording across all manpages
and B) this allows us to more reliably filter/search for protocol
specific manpages/options.

Closes #13166
2024-03-21 15:27:06 +01:00

1.1 KiB

c SPDX-License-Identifier Title Section Source See-also Protocol
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. curl CURLOPT_SSL_ENABLE_ALPN 3 libcurl
CURLOPT_SSL_ENABLE_NPN (3)
CURLOPT_SSL_OPTIONS (3)
TLS

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

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    curl_easy_setopt(curl, CURLOPT_SSL_ENABLE_ALPN, 0L);
    res = 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.