difference between call by value and call by reference in php and also $$ means?
<p>(1) I want to know what is the difference between call by value and call by reference in <code>php</code>. PHP works on call by value or call by reference?</p>

<p>(2) And also i  want to know that do you mean by $$ sign in php</p>

<p>For example:-</p>

<pre><code>$a = 'name';
$$a = "Paul";
echo $name; 

output is Paul
</code></pre>

<p>As above example what do u mean by $$ on PHP.</p>
