title: C++11-style [[unused]] attribute in gcc?
body: <p>Under gcc/g++ 4.9 I can write:</p>
  
  <pre><code>int x __attribute__((unused)) = f();
  </code></pre>
  
  <p>to indicate that x is intentionally unused.</p>
  
  <p>Is it possible to do this with the C++11 <code>[[]]</code> attribute notation somehow?</p>
  
  <p>I tried:</p>
  
  <pre><code>int x [[unused]] = f();
  </code></pre>
  
  <p>but it doesn't work.</p>
  
  <p>(Yes, I know it is an implementation-defined attribute.)</p>