CURLOPT_TCP_FASTOPEN - TCP Fast Open
#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_FASTOPEN, long enable);
CURLOPT_TCP_FASTOPEN(3) curl_easy_setopt options CURLOPT_TCP_FASTOPEN(3) NAME CURLOPT_TCP_FASTOPEN - TCP Fast Open SYNOPSIS #include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_FASTOPEN, long enable); DESCRIPTION Pass a long as parameter set to 1L to enable or 0 to disable. TCP Fast Open (RFC7413) is a mechanism that allows data to be carried in the SYN and SYN-ACK packets and consumed by the receiving end during the initial connection handshake, saving up to one full round-trip time (RTT). DEFAULT 0 PROTOCOLS All EXAMPLE CURL *curl = curl_easy_init(); if(curl) { curl_easy_setopt(curl, CURLOPT_URL, "https://example.com"); curl_easy_setopt(curl, CURLOPT_TCP_FASTOPEN, 1L); curl_easy_perform(curl); } AVAILABILITY Added in 7.49.0. This option is currently only supported on Linux and OS X El Capitan. RETURN VALUE Returns CURLE_OK if fast open is supported by the operating system, otherwise returns CURLE_NOT_BUILT_IN. ATTRIBUTES See attributes(7) for descriptions of the following attributes: +---------------+------------------+ |ATTRIBUTE TYPE | ATTRIBUTE VALUE | +---------------+------------------+ |Availability | web/curl | +---------------+------------------+ |Stability | Uncommitted | +---------------+------------------+ SEE ALSO CURLOPT_SSL_FALSESTART(3), NOTES Source code for open source software components in Oracle Solaris can be found at https://www.oracle.com/downloads/opensource/solaris-source- code-downloads.html. This software was built from source available at https://github.com/oracle/solaris-userland. The original community source was downloaded from https://curl.se/down- load/curl-7.83.1.tar.bz2. Further information about this software can be found on the open source community website at http://curl.haxx.se/. libcurl 7.83.1 November 26, 2021 CURLOPT_TCP_FASTOPEN(3)