GNURLOPT_H...TIMEOUT_MS(3)

💖 NAME 💖

okay bestie, welcome to GNURLOPT_H...TIMEOUT_MS(3) — that's the page, and it lives in the curl_easy_setopt options manual. The actual thing we're obsessing over is CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS — head start for ipv6 for happy eyeballs. periodt. 💅

🦋 SYNOPSIS 🦋

first, the include-and-call vibe:

#include <gnurl/curl.h>

CURLcode curl_easy_setopt(CURL *handle,
CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS, long timeout);

🌸 DESCRIPTION 🌸

so CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS is all about happy eyeballs. Happy eyeballs is an algorithm that attempts to connect to both IPv4 and IPv6 addresses for dual-stack hosts, preferring IPv6 first for timeout milliseconds. If the IPv6 address cannot be connected to within that time then a connection attempt is made to the IPv4 address in parallel. The first connection to be established is the one that is used. no cap, that's the whole plot. 🦋

also, the range of suggested useful values for timeout is limited. Happy Eyeballs RFC 6555 says:

“It is RECOMMENDED that connection attempts be paced 150-250 ms apart to balance human factors against network load.”

libcurl currently defaults to 200 ms. Firefox and Chrome currently default to 300 ms. iconic behavior, honestly. 🔥

🎀 DEFAULT 🎀

The default is CURL_HET_DEFAULT (currently defined as 200L). that's the standard vibe. ✨

🧚 EXAMPLE 🧚

here's the little example, copied exactly because we do not mess with the code, bestie:

CURL *curl = curl_easy_init();
if(curl) {
  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
  curl_easy_setopt(curl, CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS, 300L);

  curl_easy_perform(curl);

  /* always cleanup */
  curl_easy_cleanup(curl);
}

🌈 AVAILABILITY 🌈

Added in 7.59.0 — mark the calendar, babe. 🗓️

👑 RETURN VALUE 👑

Returns CURLE_OK. that's it, that's the return value. 💖

okay bye bestie 💋 — this page's footer says libcurl 7.59.0, 1 Feb 2018, and GNURLOPT_H...TIMEOUT_MS(3). mwah! 🫶