What can use for DateTime::diff() for PHP 5.2?

Question

Is there any function equivalent to DateTime::diff() in PHP 5.2?

My local server is PHP 5.3 and using DateTime::diff(). then I found that my live site uses PHP 5.2 a

Answer 1

Please observe that if your DateTime object was created from a date string without any timezone information (as in '2012-01-01 05:00:00' like from mysql), then setting the timezone later with DateTimeZone objects via setTimeZone() does not change the DateTime objects internal timestamp.

$localtime = new DateTime('2012-01-01 08:00:00+02:00'); // Europe/Copenhagen (+ daylight savings)
$localtime->setTimezone(new DateTimeZone('UTC')); // convert local time to utc

$utctime = new DateTime('2012-01-01 06:00:00'); // timezone assumed utc, but is in fact unknown
$utctime->setTimezone(new DateTimeZone('UTC')); // trying to rectify missing timezone which fails, because the internal timestamp isn't modified, although any other format than 'U' may indicate so
#$utctime = new DateTime('2012-01-01 06:00:00+00:00'); // timezone stated, this works

$diff = intval($localtime->format('U')) - intval($utctime->format('U'));
echo $diff; // expecting zero