Ways to detect whether a C++ virtual function has been redefined in a derived class

Question

In brief: From a C++ base-class pointer which points to an instance of a derived class, how can one determine at run-time whether a non-pure virtual functio

Answer 1

What about getting pointer to the base-class function on the first use and compare it with actual one

   class Base { virtual int foo(); }
   class Derived : public Base { virtual int foo(); }

   bool Xxx::checkOverride()
   {
       int (Base::*fpA)();
       int (Base::*fpb)();

       fpA = &Base::foo;
       fpB = &Derived::foo;

       return (fpA != fpB);
   }