title: C++ / C #define macro calculation
body: <p>Suppose I have</p>
  
  <pre><code>#define DETUNE1 sqrt(7)-sqrt(5)
  #define DETUNE2 sqrt(11)-sqrt(7)
  </code></pre>
  
  <p>And I call these multiple times in my program. </p>
  
  <p>Are DETUNE1 and DETUNE2 calculated <strong>every</strong> time it is called? </p>