初始化指向受保护成员函数的指针

Question

I have this problem:

In the header file:

class D : public B
{
//...
private:
    typedef char* (B::*psbposfun_t)() const;

    static psbposfun_t ms_aposf[2][3];
//...
};

In the source file:

D::psbposfun_t D::ms_aposf[2][3] = 
{
    {
        &B::fa1,
        &B::fa2,
        &B::fa3
    },
    {
        &B::fb1,
        &B::fb2,
        &B::fb3
    }
};

The compiler complains that the fa1 ... fb3 methods are protected. Indeed they are protected in B but I am initializing a member that belongs to D, which derives from B.

I tried initializing ms_aposf within the class (D) but the compiler complains it is not the place to initialize it.

So besides implementing a one-shot initialization in the constructor, would someone know how to circumvent this problem?

Answer 1

Use D:: instead:

D::psbposfun_t D::ms_aposf[2][3] = 
{
    {
        &D::fa1,
        &D::fa2,
        &D::fa3
    },
    {
        &D::fb1,
        &D::fb2,
        &D::fb3
    }
};

Since D is inheriting these functions, they are accessible through D , but usable as B:: pointers.