private dtor restricts instantiation to heap only

My test proves that declaration (even without definition) of a stack instance or global instance is illegal because compiler generates a (illegal) call to the private dtor!

Friend and static method can both also call the private dtor.

One usage of such a class — force all users to go trough factory to instantiate this class.

class PrivDtor{
  ~PrivDtor(){
        cout<<"dtor\n";
  }
public:
  static void destroy(PrivDtor* p){p->~PrivDtor();}
  static void del(PrivDtor* p){delete p;}
};

//PrivDtor globalInstance;  //won't compile
int main(){
  //PrivDtor stackInstance; //won't compile

  PrivDtor * p = new PrivDtor;
  //PrivDtor::del(p); // works!
  PrivDtor::destroy(p);  //works!
}

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s