The following code example is taken from the book
The C++ Standard Library - A Tutorial and Reference
by Nicolai M. Josuttis, Addison-Wesley, 1999
© Copyright Nicolai M. Josuttis 1999
#include <streambuf>
#include <locale>
#include <cstdio>
template <class charT, class traits = std::char_traits<charT> >
class basic_outbuf : public std::basic_streambuf<charT,traits>
{
protected:
/* central output function
* - print characters in uppercase mode
*/
virtual typename traits::int_type overflow (typename traits::int_type c) {
if (!traits::eq_int_type(c,traits::eof())) {
// convert lowercase to uppercase
c = std::toupper(c,getloc());
// and write the character to the standard output
if (putchar(c) == EOF) {
return traits::eof();
}
}
return traits::not_eof(c);
}
};
typedef basic_outbuf<char> outbuf;
typedef basic_outbuf<wchar_t> woutbuf;