Advanced C++ Programming Cookbook

Adding support for non-member functions to our delegate

Finally, we need to modify the delegate to add support for non-member functions. Check out this example:

bool attack(int x, int y){    return x == 42 && y == 42 ? true : false;}

To do this, we simply need to add another wrapper as follows:

template<    typename RET,    typename... ARGS    >class fun_wrapper :    public base<RET, ARGS...>{    RET (*m_func)(ARGS...);public:    fun_wrapper(RET (*func)(ARGS...)) :        m_func{func}    { }    RET func(ARGS... args) override    {        return m_func(args...);    }};

As shown in the preceding, as with our original wrapper, we store a pointer to the function we wish to call, but in this case, we do not need to store a pointer to an object as there is no object (as this is a non-member ...