PHP: call_user_func_array: pass by reference issue

Question

The below function generates error when a function contains referenced arguments eg:

function test(&$arg, &$arg2)
{
  // some code
}

Now I can not use call_user_func_array for above function, it will generate an error.

How to solve this problem?

I do need to use call_user_func_array.

Also assume that i don't know beforehand whether they are passed by reference or passed by value.

Thanks

Molten

It would be worth while for you to unaccept the current answer as it is quite literally wrong (not to mention has bad advice by abusing objects which changes the semantics of the problem completely): codepad.viper-7.com/j3GOps – Puritanical

Answer 1

A great workaround was posted on http://www.php.net/manual/de/function.call-user-func-array.php#91503

function executeHook($name, $type='hooks'){ 
    $args = func_get_args(); 
    array_shift($args); 
    array_shift($args); 
    //Rather stupid Hack for the call_user_func_array(); 
    $Args = array(); 
    foreach($args as $k => &$arg){ 
        $Args[$k] = &$arg; 
    } 
    //End Hack 
    $hooks = &$this->$type; 
    if(!isset($hooks[$name])) return false; 
    $hook = $hooks[$name]; 
    call_user_func_array($hook, $Args); 
} 

The actual hack is surrounded by comments.

Bosnia

thank you man, saved my life! this is definitely the correct answer – Abigail

Spoke too soon … While this removes the error, it wouldn't let me manipulate the referenced variable inside the callable. – Ellingston

For PHP 5.6 and above declare the function with , &...$args and then call the hook as simple as $hook(...$args). – Haffner

Answer 2

When storing your parameters in the array, make sure you are storing a reference to those parameters, it should work fine.

Ie:

call_user_func_array("test", array(&param1, &param2));

Jobbery

but what if i don't know beforehand whether they are passed by reference or passed by value? – Molten

Then figure out a way to determine that, or make them all pass by reference would be my suggestion. Not much else you can do I'm afraid. – Jobbery

Myles: what if I don't know amount of arguments in the array? – Florenceflorencia

@Florenceflorencia ultimately you need an array of references. You'll be passing something so just create an array from whatever that something is. – Jobbery

yes, right, seems call_user_func_array becomes useless in my case, i have to write spaghetti code instead of this switch(count($args)) { case 0: $class->{$method}(); break; case 1: } – Florenceflorencia