note 108836 added to function.isset

How to test for a variable actually existing, including being set to null. This will prevent errors when passing to functions. <?php // false var_export( array_key_exists('myvar', get_defined_vars()) ); $myvar; // false var_export( array_key_exists('myvar', get_defined_vars()) ); $myvar = null; // true var_export( array_key_exists('myvar', get_defined_vars()) ); unset($myvar); // false var_export( array_key_exists('myvar', get_defined_vars()) ); if (array_key_exists('myvar', get_defined_vars())) { myfunction($myvar); } ?> Note: you can't turn this into a function (e.g. is_defined($myvar)) because get_defined_vars() only gets the variables in the current scope and entering a function changes the scope. ---- Server IP: 69.147.83.197 Probable Submitter: 202.59.29.222 ---- Manual Page -- http://www.php.net/manual/en/function.isset.php Edit -- https://master.php.net/note/edit/108836 Del: integrated -- https://master.php.net/note/delete/108836/integrated Del: useless -- https://master.php.net/note/delete/108836/useless Del: bad code -- https://master.php.net/note/delete/108836/bad+code Del: spam -- https://master.php.net/note/delete/108836/spam Del: non-english -- https://master.php.net/note/delete/108836/non-english Del: in docs -- https://master.php.net/note/delete/108836/in+docs Del: other reasons-- https://master.php.net/note/delete/108836 Reject -- https://master.php.net/note/reject/108836 Search -- https://master.php.net/manage/user-notes.php