note 74455 added to language.oop5.patterns

I found that using intanceof to check whether the static variable is set, doesn't work. Consider the following example: <?php class Example{ private static $_instance = NULL public static function getInstance(){ if(!self::$_instance instanceof self){ echo "creating new Object"; self::$_instance = new self; } return self::$_instance; } } // Let's initiate an Example object: $obj = Example::getInstance(); // outputs: "creating new Object" // let's try to grab an instance of the Example object $obj = Example::getInstance(); // here we expect nothing to show up, instead, "creating new Object" appears ?> The solution is very simple, use isset instead of instanceof. Probably everyone knew this allready, but i didn't. cheers ---- Server IP: 69.147.83.197 Probable Submitter: 81.240.59.110 ---- Manual Page -- http://www.php.net/manual/en/language.oop5.patterns.php Edit -- https://master.php.net/note/edit/74455 Del: integrated -- https://master.php.net/note/delete/74455/integrated Del: useless -- https://master.php.net/note/delete/74455/useless Del: bad code -- https://master.php.net/note/delete/74455/bad+code Del: spam -- https://master.php.net/note/delete/74455/spam Del: non-english -- https://master.php.net/note/delete/74455/non-english Del: in docs -- https://master.php.net/note/delete/74455/in+docs Del: other reasons-- https://master.php.net/note/delete/74455 Reject -- https://master.php.net/note/reject/74455 Search -- https://master.php.net/manage/user-notes.php