title: What is ** in C++?
body: <p>I've seen some code, as well as some errors generated from my compiler that have a '<code>**</code>' token before the variable (eg **variablename unreferenced-- or something, I can't recall exactly offhand).  I'm fairly certain this is related to pointers, if I had to guess it looks like it's trying to dereference twice.  '<code>**</code>' is fairly ungoogleable.  Can someone point me to a good website/documentation or would someone care to explain it here?</p>
  
  <p>Thanks.</p>
  
  <p>Great responses.  If I can add, what would be some situations where it is useful to have a pointer to a pointer?  Shouldn't you just be using the original pointer instead of creating yet another pointer to the original pointer?</p>