title: What C program behaves differently in run-time when compiled with C89 and C99?
body: <p>I found the following snippet (I think in Wikipedia) that creates a different run-time when C++ comments are recognized than when not:</p>
  
  <pre><code>int a = 4 //* This is a comment, but where does it end? */ 2
    ;
  </code></pre>
  
  <p>But until now that's been the only one (variants excluded).</p>
  
  <p>I'm not interested in differentiating using <code>__STDC__</code> and the like, and not in programs that C89 will not compile.</p>
  
  <p>Are there other programs/snippets producing a different run-time with C89 than C99?</p>