note 103241 deleted from function.array-walk-recursive by danbrown

Note Submitter: tturner at derossitech dot com ---- I am using php 5.3.3. If you ever need to have your callback function take a third parameter by reference like so: function test_array_walk_recursive() { $sample = array('dog' => 'woof', 'cat' => array('angry' => 'hiss', 'happy' => 'purr'), 'aardvark' => 'kssksskss'); $flattened = array(); array_walk_recursive($sample, array($this, 'walkit'), $flattened); return($flattened); } function walkit($item, $key, &$arr) // receive as reference here { array_push($arr, $item); } one would expect $flattened to now contain a flat array of values from $sample, however this is NOT the case. It seems something odd happens because $flattened is passed to array_walk_recursive first and THEN passed to walkit and walkit does not receive $flattened as an array. In my case it received it as a string (wtf). It turns out this is because the callback is of the type call_user_func and this is a known issue with that function also. To get around it you need to set allow_call_time_pass_reference to 'On' in your php.ini file, or set it using .htaccess. You may then pass the third parameter by reference, like so: function test_array_walk_recursive() { $sample = array('dog' => 'woof', 'cat' => array('angry' => 'hiss', 'happy' => 'purr'), 'aardvark' => 'kssksskss'); $flattened = array(); array_walk_recursive($sample, array($this, 'walkit'), &$flattened); // send as reference from here return($flattened); } function walkit($item, $key, $arr) { array_push($arr, $item); } And this now does what is expected since array_walk_recursive is forced to take the parameter by reference and forward it on. If there is another way to do this without changing allow_call_time_pass_reference I would love to know how. I hate changing ini files etc!