Subj : Re: Can you mimic atexit() for class functions?
To   : borland.public.cpp.borlandcpp
From : "Benjamin Pratt" <benjamin.pratt.getridofthis@verizon.net>
Date : Wed Oct 08 2003 09:05 pm

This is a 'better' way to do the same thing in C++. You'll notice that there
is actually no function pointers at all. The previous example works, but is
not very safe. Following is the way I would recommend accomplishing your
callback container functionality:


#include <vector>
#include <iostream>

class CallbackInterface;

class CallbackContainer {
public:
   void AddCallback(CallbackInterface* pCallback) {
callbacks.push_back(pCallback); }
   void DoCallbacks();

private:
   typedef std::vector<CallbackInterface*> CALLBACKS;
   CALLBACKS callbacks;

} g_CallbackContainer;

class CallbackInterface {
public:
   CallbackInterface() { g_CallbackContainer.AddCallback(this); }
   virtual void Callback() = 0;
};

class A : public CallbackInterface {
public:
   A(int value) : _value(value) {}

   void Callback() { std::cout << "A::Callback() = " << _value <<
std::endl; }

private:
   int _value;
};

class B : public CallbackInterface {
public:
   B(float value) : _value(value) {}

   void Callback() { std::cout << "B::Callback() = " << _value <<
std::endl; }

private:
   float _value;
};

void CallbackContainer::DoCallbacks() {
 for(CALLBACKS::iterator p = callbacks.begin(); p != callbacks.end(); ++p)
    (*p)->Callback();
}

int main(void) {

 A a1(1), a2(2), a3(3);
   B b1(1.5), b2(2.5), b3(3.5);

   g_CallbackContainer.DoCallbacks();

   return 0;
}

.