Dirk Gregorius wrote: []
I saw some code that declared the copy operations private in the base class.
class Interface { public: virtual void f() = 0;
private: Interface( const Interface& ); Interface& operator=( const Interface& ); }
So in order to gain maximum style and correctness points I need to make both classes ( Interface and Implementation ) noncopyable?
Only a base class. This prevents a compiler from generating copy ctor and assignment in its successors.
Why is this possible?
Because a compiler generates copy ctor and assignment when nothing prevents it.
Does it make sense to dereference an interface?
It does make sense, since there can be functions taking an interface by reference. But dereferencing and assigning it does not.
Interface* p1 = make_interface(); Interface* p2 = make_interface();
*p1 = *p2;
Or does your example only work with auto/smart pointers?
For plain pointers also. Some say noncopyable interfaces may save from errors, though making them noncopyable I've never encountered that kind of errors. -- Maxim Yegorushkin