CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS - balls
#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS, long timeout);
curl_easy_setopt options CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS(3) NAME CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS - head start for ipv6 for happy eye- balls SYNOPSIS #include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS, long timeout); DESCRIPTION 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 par- allel. The first connection to be established is the one that is used. The range of suggested useful values for timeout is limited. Happy Eye- balls 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. DEFAULT CURL_HET_DEFAULT (currently defined as 200L) PROTOCOLS All except FILE EXAMPLE 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 RETURN VALUE Returns CURLE_OK ATTRIBUTES See attributes(7) for descriptions of the following attributes: +---------------+------------------+ |ATTRIBUTE TYPE | ATTRIBUTE VALUE | +---------------+------------------+ |Availability | web/curl | +---------------+------------------+ |Stability | Uncommitted | +---------------+------------------+ SEE ALSO CURLOPT_CONNECTTIMEOUT_MS(3), CURLOPT_TIMEOUT(3), CUR- LOPT_LOW_SPEED_LIMIT(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_HAPPY_EYEBALLS_TIMEOUT_MS(3)