I have the following code: #include <utility> #include <vector> #include <string> #include <fstream> #include <iostream> #include <map> #include #include #include #include #include #include using namespace std; void print(multimap, int> &m) { multimap, int>::iterator it1 = m.begin(); multimap, int>::iterator it2 = m.end(); for(; it1!=it2; ++it1) { cout<<"key = "<<(it1->first).first<<(it1->first).second<<"\t\t"; cout<<"value = "<<(it1->second)<, int> m1; pair par1("A", "B"); pair par2("A", "B"); pair par3("E", "F"); pair par4("E", "F"); m1.insert(pair, int>(par1,10)); m1.insert(pair, int>(par2,20)); m1.insert(pair, int>(par3,30)); m1.insert(pair, int>(par4,40)); ofstream ofs("filename"); boost::archive::text_oarchive serial1(ofs); serial1 << m1; ofs.close(); ifstream ifs("filename"); boost::archive::text_iarchive serial2(ifs); multimap, int> m2; serial2 >> m2; cout<<"map1 = "<

that I don't know what it means. Is this a normal behavior of the serialization library? I am missing something ?