Re: COMPILE!

From: JKop (NULL_at_NULL.NULL)
Date: 08/05/04 

Date: Thu, 05 Aug 2004 18:07:34 GMT

>> ~AutoDestructive()
>> {
>> this->CleanUp();
>
> There's your problem - calling a virtual function from a destructor
> doesn't do what you think it does. Calling a pure virtual function
> from a destructor causes undefined behaviour (and fortunately VC seems
> to indicate this with a linker error, which is as nice as undefined
> behaviour gets).
>
> Basically, destruction goes for typical implementations:
>
> derived class destructor called
> derived members destructed in reverse order of declaration
> *vtable pointer updated to point to base class vtable*
> base class destructor called
> base class members destructed in reverse order of declaration
>
> The emphasised line is what causes the problem for you - calling a
> virtual function from a constructor or destructor calls the function
> in the base object currently being constructed or destructed, not the
> one in the most derived class.
>
> Tom

Okay, is there anything wrong with the following though? It compiles for me:

class Base
{
public:

            virtual void Monkey() = 0;

            void HelperMonkey()
            {
                        this->Monkey();
            }

            ~Base()
            {
                HelperMonkey();
            }
};

class Derived : public Base
{
public:

            virtual void Monkey()
            {

            }
};

int main()
{
            Derived checker;
}

-JKop

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