title: C++ type traits to check if class has operator/member
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/257288/is-it-possible-to-write-a-c-template-to-check-for-a-functions-existence">Is it possible to write a C++ template to check for a function&#39;s existence?</a>  </p>
  </blockquote>
  
  
  
  <p>Is it possible to use boost type traits or some other mechanism to check if a particular template parameter has an operator/function, e.g. <code>std::vector</code> as a template parameter has <code>operator[]</code>, while <code>std::pair</code> does not.</p>