romenskiy2012/curl

mirror of https://github.com/curl/curl.git synced 2026-04-27 22:52:12 +03:00

Daniel Stenberg 54ded66618

docs/libcurl: improve easy setopt examples

- always assign the curl_easy_perform() return code (and declare
  the necessary 'result' variable for it)

- always call curl_easy_cleanup() on the created easy handles

Closes #21364

2026-04-18 23:34:39 +02:00

1.4 KiB

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SPDX-License-Identifier

Title

Section

Source

See-also

Protocol

Added-in

curl

CURLOPT_TCP_FASTOPEN

libcurl

CURLOPT_SSL_FALSESTART (3)

TCP

7.49.0

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 (RFC 7413) 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).

Beware: the TLS session cache does not work when TCP Fast Open is enabled. TCP Fast Open is also known to be problematic on or across certain networks.

DEFAULT

%PROTOCOLS%

EXAMPLE

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
    curl_easy_setopt(curl, CURLOPT_TCP_FASTOPEN, 1L);
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

NOTES

This option is only supported on Linux and macOS 10.11 or later.

%AVAILABILITY%

RETURN VALUE

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).

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