template <class charT, class traits>
bool operator!=(const istreambuf_iterator<charT, traits>& a,
const istreambuf_iterator<charT, traits>& b);
template <class charT, class traits>
bool operator!=(default_sentinel a,
const istreambuf_iterator<charT, traits>& b);
template <class charT, class traits>
bool operator!=(const istreambuf_iterator<charT, traits>& a,
default_sentinel b);
Effects: Equivalent to: return !(a == b);