PHP: call_user_func_array: pass by reference issue

Question

Hello,

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

Answer 1

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));

Answer 2

You cannot pass arguments by reference to functions called with callbacks. The reason is that call_user_func_array()s parameters are not references. If you really need to do it with a callback, you will need to wrap the parameters into an object (objects are always passed by reference):

function test($params) {
    echo $params->param1;
    echo $params->param2;
}
$params = (object) array('param1' => $param1, 'param2' => $param2);
call_user_func_array('test', array($params));

Answer 3

I'm getting a similar issue with drupal project OpenScholar on Fedora with php 5.3.x.

warning: call_user_func_array() expects parameter 2 to be array, string given in /var/www/html/sites/all/modules/contrib/views/views.module on line 451.

I'm trying the following test. Taking line 451 from

   if (function_exists($callback) && call_user_func_array($callback, $argments)) {
     return TRUE;
   }

to (notice: array($argments))

   if (function_exists($callback) && call_user_func_array($callback, array($argments))) {
 return TRUE;

}

This seem to work for me! :)