This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 118e. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2025-11-05

7. Can a class with a private virtual base class be derived from?

Section: 11.8.3  [class.access.base]     Status: NAD     Submitter: Jason Merrill     Date: unknown
    class Foo { public: Foo() {}  ~Foo() {} };
    class A : virtual private Foo { public: A() {}  ~A() {} };
    class Bar : public A { public: Bar() {}  ~Bar() {} };
~Bar() calls ~Foo(), which is ill-formed due to access violation, right? (Bar's constructor has the same problem since it needs to call Foo's constructor.) There seems to be some disagreement among compilers. Sun, IBM and g++ reject the testcase, EDG and HP accept it. Perhaps this case should be clarified by a note in the draft.

In short, it looks like a class with a virtual private base can't be derived from.

Rationale: This is what was intended.