title: "class not registered" which class?
body: <p>Consider this code:</p>
  
  <pre><code>try {
      ISomeObject pObj(__uuidof(SomeClass));
      ISomeObject pObj2(__uuidof(SomeOtherClass));
  } catch ( _com_error&amp; e ) {
      // Log what failed
  }
  </code></pre>
  
  <p>I.e. I have a block of code which instanciates my objects. 
  Sometimes (a bad install) it failes because some class wasn't properly registered.
  (I don't have a particular problem, rather general discussion here.)</p>
  
  <p>Is there some way to, from the caught exception or otherwise, realize what class failed?
  A have pondered to make a wrapper of my own which stores a variable like <em>gLastCreateAttemptUuid</em>, but it feel cumbersome.</p>
  
  <p>Also, suppose that SomeClass in turn attempt to instanciate something else, which isn't registered. Can one then figure out the underlying issue?</p>