Simulating the Elisp advice mechanism in C++

class A
{
public:
   void foo();
}

class B
{
private:
    A* a;

public:
    B(A* a)
    {
       this->a = a;
    }

    void pre();  /* function that gets called prior to A::foo */
    void post(); /* function that gets called after A::foo */
    void foo();  /* To use the wrapper class,call B::foo instead of A::foo */
    {
       pre();
       a->foo();
       post();
    }
}