title: PHP How to know if a variable is a reference?
body: <p>I want to call a function with call_user_func_array but i noticed that if an argument is a reference in the function definition and is a simple value in call_user_func_array, the following warning appears:
  Warning:  Parameter 1 to test() expected to be a reference, value given</p>
  
  <p>Here is a simple example of what i am trying to do:</p>
  
  <pre><code>&lt;?php
  $a = 0;
  $args = array($a);
  function test(&amp;$a) {
      $a++;
  }
  $a = 0;
  call_user_func_array('test', $args);
  ?&gt;
  </code></pre>
  
  <p>My question is: how can i know if a value (in this case the first value of $args) is a reference or not ?</p>