QExplicitlySharedPointer and inheritance

问题

What is the best way to use QExplicitlySharedPointer and inherited classes. I would like when the BaseClass exits on it's own to have a my d pointer be QExplicitlySharedPointer<BaseClassPrivate> and when I have a Derived class on top of this base class I'd like to have d be a QExplicitlySharedPointer<DerivedClassPrivate>.

I tried making DerivedClassPrivate inherit from BaseClassPrivate, and then make the d pointer protected and re-define the d-pointer in my derived class, but it seems now that I have two copies of the d-pointer both local to the class they are defined in... which is not what I want.

回答1:

What about this:

template< typename P = BaseClassPrivate >
class BaseClass
{
public:
  void myBaseFunc() { d->myBaseFunc(); }
protected:
  QExplicitlySharedDataPointer< P > d;
};

class DerivedClass : public BaseClass< DerivedClassPrivate >
{
public:
  void myDerivedFunc() { d->myDerivedFunc(); }
};

来源：https://stackoverflow.com/questions/2693319/qexplicitlysharedpointer-and-inheritance