Question

C++ has so much stuff that I don’t know.

Is there any way to create a function within a class, that will always be called whenever any other function of that class is called? (like making the function attach itself to the first execution path of a function)

I know this is tricky but I’m curious.

Answer 1

Yes-ish, with a bit of extra code, some indirection and another class and using the -> instead of the . operator.

// The class for which calling any method should call PreMethod first. class DogImplementation { public:    void PreMethod();    void Bark(); private:    DogImplementation(); // constructor private so can only be created via smart-pointer.    friend class Dog; // can access constructor. };  // A 'smart-pointer' that wraps a DogImplementation to give you // more control. class Dog { public:    DogImplementation* operator -> ()    {        _impl.PreMethod();        return &_impl;    } private:    DogImplementation _impl; };  // Example usage of the smart pointer. Use -> instead of . void UseDog() {   Dog dog;   dog->Bark();    // will call DogImplementation::PreMethod, then DogImplementation::Bark } 

Well.. something roughly along those lines could be developed into a solution that I think would allow you to do what you want. What I’ve sketched out there probably won’t compile, but is just to give you a starting point.