Класс, который знает все свои экземпляры

template< class T >
class ClassWhoKnowsAllHisInstances
{
   static std::list<  T* > classList;
public:
  ClassWhoKnowsAllHisInstances()
  {  
    classList.push_back((T *)this);
  }; 
  ~ClassWhoKnowsAllHisInstances()
  {  
    std::list< T* >::iterator it;
    it=(std::find(classList.begin(), classList.end(), 
        ( T* ) this));
    if(it!=classList.end())
      classList.erase(it);
  };
};

class MyClassWithListOfAllInstances : public ClassWhoKnowsAllHisInstances< MyClassWithListOfAllInstances>
{

};

class OtherClassWhoKnowsAllItInstances : public ClassWhoKnowsAllHisInstances< OtherClassWhoKnowsAllItInstances >
{

};