note 109737 added to language.oop5.references

The use of clone may get you the behavior you expect when passing an object to a function, as shown below using DateTime objects as examples. <?php date_default_timezone_set( "America/Detroit" ); $a = new DateTime; echo "a = " . $a->format('Y-m-j') . "\n"; // This might not give what you expect... $b = upDate( $a ); // a and b both updated echo "a = " . $a->format('Y-m-j') . ", b = " . $b->format('Y-m-j') . "\n"; $a->modify( "+ 1 day" ); // a and b both modified echo "a = " . $a->format('Y-m-j') . ", b = " . $b->format('Y-m-j') . "\n"; // This might be what you want... $c = upDateClone( $a ); // only c updated, a left alone echo "a = " . $a->format('Y-m-j') . ", c = " . $c->format('Y-m-j') . "\n"; function upDate( $datetime ) { $datetime->modify( "+ 1 day" ); return $datetime; } function upDateClone( $datetime ) { $dt = clone $datetime; $dt->modify( "+ 1 day" ); return $dt; } ?> The above would output something like: a = 2012-08-15 a = 2012-08-16, b = 2012-08-16 a = 2012-08-17, b = 2012-08-17 a = 2012-08-17, c = 2012-08-18 ---- Server IP: 69.147.83.197 Probable Submitter: 198.109.51.204 ---- Manual Page -- http://www.php.net/manual/en/language.oop5.references.php Edit -- https://master.php.net/note/edit/109737 Del: integrated -- https://master.php.net/note/delete/109737/integrated Del: useless -- https://master.php.net/note/delete/109737/useless Del: bad code -- https://master.php.net/note/delete/109737/bad+code Del: spam -- https://master.php.net/note/delete/109737/spam Del: non-english -- https://master.php.net/note/delete/109737/non-english Del: in docs -- https://master.php.net/note/delete/109737/in+docs Del: other reasons-- https://master.php.net/note/delete/109737 Reject -- https://master.php.net/note/reject/109737 Search -- https://master.php.net/manage/user-notes.php