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

I don't know how to do such detection, but did you consider use of static polymorphism instead? Optimizations can be done at compile-time if every virtual method of Equation is replaced with a template "policy" with default value.

//default implementation of a virtual method turned into a functor
//which optionally takes a reference to equation
class DefaultFunctor1
{
public:
    //...
    double operator()(double x) { return log(x); }
};
template
class Equation
{
public:
    typedef F1 Functor1;
    //...
private:
    F1 f1;
};
class Solver
{
public:
    //....
    template
    void solve(Equation& eq)
    {
        Loki::Int2Type<
                        Loki::IsSameType::value
                       > selector;
        //choose at compile time appropriate implementation among overloads of doSolve
        doSolve(selector);
    }
private:
    //.... overloads of doSolve here
};
int main()
{
    Equation<> eq;
    Solver solver;
    solver.solve(eq); //calls optimized version
    Equation my_eq;
    solver.solve(my_eq); //calls generic version
    return 0;
}