title: best-practice on C header files with #ifndef #define #endif
body: <p>what is concerned best practice regarding the following "pattern"?</p>
  
  <pre><code>#ifndef BLAFOO_H
  #define BLAFOO_H
  /* ...
   * ...
   */
  #endif /* BLAFOO_H */
  </code></pre>
  
  <p>how should i name the header in the <code>#define</code> directive? i've seen all from said <code>BLAFOO_H</code> to <code>__BLAFOO_H</code> to <code>_BLAFOO_H_</code> etc..</p>