title: switch case: error: case label does not reduce to an integer constant
body: <pre><code>int value;
  
  const int signalmin = some_function();
  
  switch(value)
  {
     case signalmin:
     break;
  }
  </code></pre>
  
  <p>I read the value of some_function and use that int value to do a switch case on. The C99 compiler gives back:</p>
  
  <blockquote>
    <p>error: case label does not reduce to an integer constant</p>
  </blockquote>
  
  <p>But I cannot use a <code>#define</code> because the int value is being read before the switch executes.</p>