title: system() returns bad exit code
body: <p>I am using <code>system</code> to call an external application and I need to interpret its exit code.</p>
  
  <p>I know that <code>system</code> returns the exit code from the command multiplied by 256, but when in <code>foo.bat</code> I write <code>exit 256</code> the result is zero.</p>
  
  <p>Why is this happening?</p>