title: Does an undefined symbol from a vtable imply an error between interface and implementation?
body: <p>Does this kind of error implicate an error between an interface and its implementation?</p>
  
  <pre><code>Undefined symbols for architecture i386:
    "MyClass::ChangeManager::GetChanges(
         MyClass::ObjectId, 
         MyClass::IChangeManager::Changes&amp;, 
         bool)"
    , referenced from:
    vtable for MyClass::ChangeManager in libMobileUtils.a(ChangeManager.o)
  </code></pre>