#include <iostream>
#include <boost/foreach.hpp>
#include <boost/unordered_map.hpp>

typedef boost::unordered_map<std::string, std::string> map_type;

std::ostream&
operator<<(std::ostream& o, const map_type& m)
{
  o << "size: " << m.size();
  BOOST_FOREACH (const map_type::value_type& p, m)
    o << ", " << p.first << " => " << p.second;
  return o;
}

map_type
make_map()
{
  map_type res;
  res["foo"] = "FOO";
  res["bar"] = "BAR";
  std::cerr << "make_map:   " << res << std::endl;
  return res;
}

map_type
return_map()
{
  const map_type& res = make_map();
  std::cerr << "return_map: " << res << std::endl;
  return res;
}

int
main()
{
  map_type map = return_map();
  std::cerr << "main:       " << map << std::endl;
}