(PHP 5 >= 5.5.0, PHP 7, PECL >= 3.0.0a1)
IntlTimeZone::getCanonicalID — Get the canonical system timezone ID or the normalized custom time zone ID for the given time zone ID
$zoneId
[, bool &$isSystemID
] )
This function is currently not documented; only its argument list is available.
zoneId
isSystemID