title: Is it possible to output a variable from a header file?
body: <p>Suppose I have a header file with lines like this:</p>
  
  <pre><code>#if LONG_BIT != 8 * SIZEOF_LONG
  /* 04-Oct-2000 LONG_BIT is apparently (mis)defined as 64 on some recent
   * 32-bit platforms using gcc.  We try to catch that here at compile-time
   * rather than waiting for integer multiplication to trigger bogus
   * overflows.
   */
  #error "pp897:  LONG_BIT  definition appears wrong for platform (bad gcc/glibc config?)."
  #endif
  </code></pre>
  
  <p>I would like to output the value of LONG_BIT and SIZEOF_LONG.  Is it possible to do this, or is that impossible from a header file?</p>