title: Passing by constant reference in the lambda capture list
body: <p>I'm building a lambda function that requires access to a fair number of variables in the context.</p>
  
  <pre><code>const double defaultAmount = [&amp;]{
      /*ToDo*/
  }();
  </code></pre>
  
  <p>I'd rather not use <code>[=]</code> in the list as I don't want lots of value copies to be made.</p>
  
  <p>I'm concerned about program stability if I use <code>[&amp;]</code> since I don't want the lambda to modify the capture set.</p>
  
  <p>Can I pass by const reference? <code>[const &amp;]</code> doesn't work.</p>
  
  <p>Perhaps a good compiler optimises out value copies, so <code>[=]</code> is preferable.</p>