namespace std {
template<class charT, class traits = char_traits<charT>>
class basic_ostream;
using ostream = basic_ostream<char>;
using wostream = basic_ostream<wchar_t>;
template<class charT, class traits>
basic_ostream<charT, traits>& endl(basic_ostream<charT, traits>& os);
template<class charT, class traits>
basic_ostream<charT, traits>& ends(basic_ostream<charT, traits>& os);
template<class charT, class traits>
basic_ostream<charT, traits>& flush(basic_ostream<charT, traits>& os);
template<class charT, class traits>
basic_ostream<charT, traits>& emit_on_flush(basic_ostream<charT, traits>& os);
template<class charT, class traits>
basic_ostream<charT, traits>& noemit_on_flush(basic_ostream<charT, traits>& os);
template<class charT, class traits>
basic_ostream<charT, traits>& flush_emit(basic_ostream<charT, traits>& os);
template<class charT, class traits, class T>
basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>&& os, const T& x);
}