title: What does "x" mean in the typical xstr macro?
body: <p>It's common practice to define stringizing macros like:</p>
  
  <pre><code>#define str(token) #token
  #define xstr(token) str(token)
  </code></pre>
  
  <p>Why is the <code>x</code> prefix typically used?  Is there any meaning to "x"?</p>
  
  <p>(My guess would be that maybe it stands for "expanded" (if anything), but I have no evidence to back that up.)</p>