note 126102 added to datetime.settime

Be aware that setTime can cause a change in the timezone offset: https://3v4l.org/MqYN9 (The time 01:05:00 exists twice on this day in Europe/London due to DST change - once in +01:00 and then again at +00:00) $tzUK = new \DateTimeZone("Europe/London"); $tzUtc = new \DateTimeZone("UTC"); $dt = \DateTimeImmutable::createFromFormat("!Y-m-d H:i:s", "2020-10-25 00:05:00", $tzUtc); $dt = DateTime::createFromFormat('U', $dt->format('U')); print $dt->format(\DateTime::RFC3339 ." e") ."\n"; $dt->setTimeZone($tzUK); print $dt->format(\DateTime::RFC3339 ." e") ."\n"; $dt->setTime((int) $dt->format('H'), (int) $dt->format('i'), 0); print $dt->format(\DateTime::RFC3339 ." e") ."\n"; Will output: 2020-10-25T00:05:00+00:00 +00:00 2020-10-25T01:05:00+01:00 Europe/London 2020-10-25T01:05:00+00:00 Europe/London Verified on PHP 5.3 thru 8.0 (latest at time of posting) ---- Server IP: 45.112.84.4 Probable Submitter: 45.112.85.242 (proxied: 82.44.111.98) ---- Manual Page -- https://php.net/manual/en/datetime.settime.php Edit -- https://main.php.net/note/edit/126102 Del: integrated -- https://main.php.net/note/delete/126102/integrated Del: useless -- https://main.php.net/note/delete/126102/useless Del: bad code -- https://main.php.net/note/delete/126102/bad+code Del: spam -- https://main.php.net/note/delete/126102/spam Del: non-english -- https://main.php.net/note/delete/126102/non-english Del: in docs -- https://main.php.net/note/delete/126102/in+docs Del: other reasons-- https://main.php.net/note/delete/126102 Reject -- https://main.php.net/note/reject/126102 Search -- https://main.php.net/manage/user-notes.php