note 103603 added to function.isset

isset() returns TRUE if a value is NULL. That seems wrong to me as there is no way to distinguish between a value set to NULL and a truly undefined value. If you have this problem inside a class, there is a fix: class T { function has_attribute($att) { $props = get_object_vars($this); return array_key_exists($att, $props); } } $x = new T(); $x->foo_exists = 4; var_dump($x->has_attribute('foo_exists')); // TRUE var_dump($x->has_attribute('bar_exists')); // FALSE ---- Server IP: 69.147.83.197 Probable Submitter: 72.194.208.80 ---- Manual Page -- http://www.php.net/manual/en/function.isset.php Edit -- https://master.php.net/note/edit/103603 Del: integrated -- https://master.php.net/note/delete/103603/integrated Del: useless -- https://master.php.net/note/delete/103603/useless Del: bad code -- https://master.php.net/note/delete/103603/bad+code Del: spam -- https://master.php.net/note/delete/103603/spam Del: non-english -- https://master.php.net/note/delete/103603/non-english Del: in docs -- https://master.php.net/note/delete/103603/in+docs Del: other reasons-- https://master.php.net/note/delete/103603 Reject -- https://master.php.net/note/reject/103603 Search -- https://master.php.net/manage/user-notes.php