1--- 2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3SPDX-License-Identifier: curl 4Title: CURLOPT_SSL_FALSESTART 5Section: 3 6Source: libcurl 7See-also: 8 - CURLOPT_TCP_FASTOPEN (3) 9Protocol: 10 - TLS 11TLS-backend: 12 - Secure Transport 13--- 14 15# NAME 16 17CURLOPT_SSL_FALSESTART - TLS false start 18 19# SYNOPSIS 20 21~~~c 22#include <curl/curl.h> 23 24CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_FALSESTART, long enable); 25~~~ 26 27# DESCRIPTION 28 29Pass a long as parameter set to 1L to enable or 0 to disable. 30 31This option determines whether libcurl should use false start during the TLS 32handshake. False start is a mode where a TLS client starts sending application 33data before verifying the server's Finished message, thus saving a round trip 34when performing a full handshake. 35 36# DEFAULT 37 380 39 40# EXAMPLE 41 42~~~c 43int main(void) 44{ 45 CURL *curl = curl_easy_init(); 46 if(curl) { 47 curl_easy_setopt(curl, CURLOPT_URL, "https://example.com"); 48 curl_easy_setopt(curl, CURLOPT_SSL_FALSESTART, 1L); 49 curl_easy_perform(curl); 50 } 51} 52~~~ 53 54# AVAILABILITY 55 56Added in 7.42.0. This option is currently only supported by the Secure 57Transport (on iOS 7.0 or later, or OS X 10.9 or later) TLS backend. 58 59# RETURN VALUE 60 61Returns CURLE_OK if false start is supported by the SSL backend, otherwise 62returns CURLE_NOT_BUILT_IN. 63