#include <vector>
    #include <iostream>
 
    typedef void* SESSION;       // Or whatever it is
    typedef void* DELIVERY_MODE; // You didn't say what these are
    typedef void* (*Func) (SESSION, DELIVERY_MODE, DELIVERY_MODE);
    typedef std::vector<Func> FuncVector;
 
    FuncVector f_callbackVector;
    FuncVector::iterator f_callbackVectorIterator = f_callbackVector.begin();
 
    void* handleDeliveryModeChange
    (
      SESSION s,
      const DELIVERY_MODE d1,
      const DELIVERY_MODE d2
    )
    {
      if ((*f_callbackVectorIterator) == &handleDeliveryModeChange)
      {
        std::cout << "\n\n\n\nWOW\n\n\n\n";
      }
    }
 
    int main()
    {
 
      f_callbackVector.push_back(handleDeliveryModeChange);
    }

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