Regarding CURLE_OPERATION_TIMEDOUT vs. CURLE_OPERATION_TIMEOUTED:
Originally cURL had the constant named TIMEOUTED (read: "timeout-ed"). This was changed[1] in 2007 and v7.17.0 to be TIMEDOUT (read: "timed out") and the old constant kept in place as an alias.
PHP started off using TIMEOUTED as well. The TIMEDOUT constant was added[2] in 2012 and v5.5.0 and the old constant was *kept in place*.
If you ask me, the TIMEDOUT constant reads more nicely (not to mention is technically the correct one to use) and as long as you're using PHP 5.5+ then it is available. If you have to support older versions then I suggest you keep using the new constant and add a polyfill like
<?php
if (version_compare(PHP_VERSION, "5.5.0", "<")) {
define("CURLE_OPERATION_TIMEDOUT", CURLE_OPERATION_TIMEOUTED);
}
?>
or
<?php
// PHP <5.5.0
defined("CURLE_OPERATION_TIMEDOUT") || define("CURLE_OPERATION_TIMEDOUT", CURLE_OPERATION_TIMEOUTED);
?>
to be removed once you stop supporting them.
[1] https://github.com/bagder/curl/commit/9f44a95522162c0f4a61093efe1bf1f58b087358#diff-d8c6cb80505e0f7d5e27fca2a682aa34L119
[2] https://github.com/php/php-src/commit/9ab45d3edbafa3ee751472c3f8d1fb3f51f38cf1#diff-ac978e3de205f1d14eb960e0eb15ef24R723