title: What do numbers using 0x notation mean?
body: <p>What does a <code>0x</code> prefix on a number mean?</p>
  
  <pre><code>const int shared_segment_size = 0x6400;
  </code></pre>
  
  <p>It's from a C program. I can't recall what it amounts to and particularly what the letter <code>x</code> means.</p>