struct String
{
    String(const char* ss)
    :s(ss)
    {
        std::cout << "cons" << std::endl;
    }
    operator const char*() const { return s.c_str(); }
    std::string s;
};

bool compare(const char* a, const char* b)
{
    return strcmp(a, b) < 0;
}

std::map<String, int, bool(*)(const char*,const char*)> test(compare);
    test.insert(std::make_pair("test", 1));
    std::cout << test.find("test")->second << std::endl;