CURLOPT_TCP_FASTOPEN man page

CURLOPT_TCP_FASTOPEN — enable 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, "http://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.

Referenced By

curl_easy_setopt(3).

May 15, 2017 libcurl 7.57.0 curl_easy_setopt options