This does not works. Please fix it!

#include <iostream>

#include <streambuf>
#include <locale>
#include <cstdio>

template<class charT, class traits = std::char_traits<charT> >
class basic_myoutbuf : public std::basic_streambuf<charT, traits>
{
protected:
    virtual typename traits::int_type overflow( typename traits::int_type c)
    {
        if ( ! traits::eq_int_type(c, traits::eof()) )
        {
            c = std::toupper(c,getloc());
            if ( putchar(c) == EOF )
                return traits::eof();
        }
        return c;
    }
};

typedef basic_myoutbuf<char> myoutbuf;

int main()
{
    myoutbuf ob;
    std::cout.rdbuf(&ob);

    std::cout << "Hello world" << std::endl;
    return 0;
}