note 99386 modified in class.datetime by davey

please note that using setTimezone setTimestamp setDate setTime etc.. will modify the original object, and the return value is $this $original = new DateTime("now"); $modified = $original->setTimezone(new DateTimezone("europe/rome")); echo $original === $modified ? "THE OBJECT IS THE SAME" : "OBJECTS ARE DIFFERENT"; so a datetime object is mutable (Editors note: PHP 5.5 adds DateTimeImmutable which does not modify the original object, instead creating a new instance.) --was-- please note that using setTimezone setTimestamp setDate setTime etc.. will modify the original object, and the return value is $this $original = new DateTime("now"); $modified = $original->setTimezone(new DateTimezone("europe/rome")); echo $original === $modified ? "THE OBJECT IS THE SAME" : "OBJECTS ARE DIFFERENT"; so a datetime object is mutable (Editors note: PHP 5.5 adds DateTimeImmutable which does not modify the original object, instead creating a new instance.) http://php.net/manual/en/class.datetime.php