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