title: When to pass a pointer to pointer as argument to functions in C++?
body: <p><a href="http://www.geeksforgeeks.org/when-do-we-pass-arguments-by-reference-or-pointer/" rel="nofollow">Here</a> i read an article about when to pass pointers as argument of functions. But i want to know about some situations in which you should pass a pointer to pointer as argument of a function.
  To be more clear i want to know when one should use something like:</p>
  
  <pre><code>func(int **x);
  </code></pre>