title: double stars in pointer definition
body: <p>I have a come across following definition in an embedded code:</p>
  
  <pre><code>#define REG_ADD 0x20081004
  #define pREG ((void * volatile *)REG_ADD)
  </code></pre>
  
  <p>Why there are 2 <code>*</code> in <code>pREG</code> definition? What does it mean?</p>