title: Return empty std::pair from function
body: <p>Is it possible to return an empty pair from a function? Meaning, follow the rules of the function prototype, but do not have any elements in the pair (e.g. NULL). Understanding that a pair simply exists so I don't know if this is conceptually possible. I have a need to return a pair that is NULL or empty, if that makes any sense.</p>
  
  <p>For example,</p>
  
  <pre><code>pair&lt;int, int&gt; MyClass::someFunction()
  {
  
     // do something that means we need to return an empty pair
     return NULL; // &lt;--- this does not work obviously
  }
  </code></pre>
  
  <p>Unfortunately, boost is not a possibility for me.</p>