Sample of use of codecvt_utf8.

This class is part of C++0x. "Standard code conversion facets"

#include <fstream>
#include <codecvt>
#include <string>
using namespace std;

int main()
{

        // writing
    {
        std::locale ulocale(locale(), new codecvt_utf8<wchar_t>) ;
        std::wofstream ofs("test.txt");
        ofs.imbue(ulocale);
        ofs << L"maçã"; //apple in portuguese
        
        }

        // reading
    {
        std::locale ulocale(locale(), new codecvt_utf8<wchar_t>) ;
        std::wifstream ifs("test.txt");
        ifs.imbue(ulocale);
        std::wstring ws;
        std::getline(ifs, ws);      
    }
}

(compiled using VC++ 2010 express)