curl/docs/libcurl/opts/CURLOPT_SSL_FALSESTART.md
Daniel Stenberg eefcc1bda4
docs: introduce "curldown" for libcurl man page format
curldown is this new file format for libcurl man pages. It is markdown
inspired with differences:

- Each file has a set of leading headers with meta-data
- Supports a small subset of markdown
- Uses .md file extensions for editors/IDE/GitHub to treat them nicely
- Generates man pages very similar to the previous ones
- Generates man pages that still convert nicely to HTML on the website
- Detects and highlights mentions of curl symbols automatically (when
  their man page section is specified)

tools:

- cd2nroff: converts from curldown to nroff man page
- nroff2cd: convert an (old) nroff man page to curldown
- cdall: convert many nroff pages to curldown versions
- cd2cd: verifies and updates a curldown to latest curldown

This setup generates .3 versions of all the curldown versions at build time.

CI:

Since the documentation is now technically markdown in the eyes of many
things, the CI runs many more tests and checks on this documentation,
including proselint, link checkers and tests that make sure we capitalize the
first letter after a period...

Closes #12730
2024-01-23 00:29:02 +01:00

63 lines
1.3 KiB
Markdown

---
c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_SSL_FALSESTART
Section: 3
Source: libcurl
See-also:
- CURLOPT_TCP_FASTOPEN (3)
---
# 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
# PROTOCOLS
All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.
# 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);
}
}
~~~
# AVAILABILITY
Added in 7.42.0. This option is currently only supported by the Secure
Transport (on iOS 7.0 or later, or OS X 10.9 or later) TLS backend.
# RETURN VALUE
Returns CURLE_OK if false start is supported by the SSL backend, otherwise
returns CURLE_NOT_BUILT_IN.