Hi there,

I am testing the following sample code on page 264 of the book "Beyond the C++ Standard Library" and got an error msg: "result_type' : is not a member of '`global namespace'' from MSVC 2008 Pro compiler. Can anyone point out what is wrong with it? Thanks.
------------
#include<iostream>
#include<string>
#include<map>
#include<vector>
#include<algorithm>
#include "boost/bind.hpp"

class print_size {
    typedef std::map<std::string, std::vector<int> > map_type;
public:
    typedef void result_type;
    result_type operator()(std::ostream& os, const map_type::value_type& x) const {
        os << x.second.size() << '\n';
    }
};

int main() {
    typedef std::map<std::string, std::vector<int> > map_type;
    map_type m;
    m["Strange?"].push_back(1);
    m["Strange?"].push_back(2);
    m["Wierd?"].push_back(3);
    m["Wierd?"].push_back(4);
    m["Wierd?"].push_back(5);

    std::for_each(m.begin(), m.end(),
        boost::bind(&print_size(), boost::ref(std::cout), _1));
}
------------