curl/docs/libcurl/opts/CURLOPT_SSL_FALSESTART.md
Daniel Stenberg 8c1d9378ac
curldown: make 'added-in:' a mandatory header field
- generate AVAILABILITY manpage sections automatically - for consistent
  wording

- allows us to double-check against other documumentation (symbols-in-versions
  etc)

- enables proper automation/scripting based on this data

- lots of them were wrong or missing in the manpages

- several of them repeated (sometimes mismatching) backend support info

Add test 1488 to verify "added-in" version numbers against
symbols-in-versions.

Closes #14217
2024-07-18 18:04:09 +02:00

58 lines
1.1 KiB
Markdown

---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_SSL_FALSESTART
Section: 3
Source: libcurl
See-also:
- CURLOPT_TCP_FASTOPEN (3)
Protocol:
- TLS
TLS-backend:
- Secure Transport
Added-in: 7.42.0
---
# NAME
CURLOPT_SSL_FALSESTART - TLS false start
# SYNOPSIS
~~~c
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_FALSESTART, long enable);
~~~
# DESCRIPTION
Pass a long as parameter set to 1L to enable or 0 to disable.
This option determines whether libcurl should use false start during the TLS
handshake. False start is a mode where a TLS client starts sending application
data before verifying the server's Finished message, thus saving a round trip
when performing a full handshake.
# DEFAULT
0
# EXAMPLE
~~~c
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
curl_easy_setopt(curl, CURLOPT_SSL_FALSESTART, 1L);
curl_easy_perform(curl);
}
}
~~~
# RETURN VALUE
Returns CURLE_OK if false start is supported by the SSL backend, otherwise
returns CURLE_NOT_BUILT_IN.