note 113261 added to datetime.add

Be careful that the internal timer to your DateTime object can be changed drastically when adding even 1 second, during the switch from DST to normal. Consider the following: <?php $ts = 1383458399; /* 2013-11-03 01:59:59 in Eastern Saving Time */ $dst = DateTime::createFromFormat('U',$ts, new DateTimeZone('GMT')); /* timezone is ignored for a unix timestamp, but if we don't put it, php throws warnings */ $dst->setTimeZone(new DateTimeZone('EST5EDT')); /* a timezone effectuating the change */ $second = new DateInterval('PT1S'); /* one second */ echo $ts . "\t" . $dst->format("U\tY-m-d H:i:s T") . "\n"; $dst->add($second); $ts++; echo $ts . "\t" . $dst->format("U\tY-m-d H:i:s T") . "\n"; /* results: 1383458399 1383458399 2013-11-03 01:59:59 EDT 1383458400 1383462000 2013-11-03 02:00:00 EST noticed how the second column went from 1383458399 to 1383462000 even though only 1 second was added? */ ?> ---- Server IP: 69.147.83.199 Probable Submitter: 199.231.184.141 ---- Manual Page -- http://php.net/manual/en/datetime.add.php Edit -- https://master.php.net/note/edit/113261 Del: integrated -- https://master.php.net/note/delete/113261/integrated Del: useless -- https://master.php.net/note/delete/113261/useless Del: bad code -- https://master.php.net/note/delete/113261/bad+code Del: spam -- https://master.php.net/note/delete/113261/spam Del: non-english -- https://master.php.net/note/delete/113261/non-english Del: in docs -- https://master.php.net/note/delete/113261/in+docs Del: other reasons-- https://master.php.net/note/delete/113261 Reject -- https://master.php.net/note/reject/113261 Search -- https://master.php.net/manage/user-notes.php