27 Input/output library [input.output]

27.7 Formatting and manipulators [iostream.format]

27.7.2 Input streams [input.streams]

27.7.2.5 Rvalue stream extraction [istream.rvalue]

template <class charT, class traits, class T> basic_istream<charT, traits>& operator>>(basic_istream<charT, traits>&& is, T&& x);

1

Effects: Equivalent to: 

is >> std::forward<T>(x);
return is;
2

Remarks: This function shall not participate in overload resolution unless the expression is >> std::forward<T>(x) is well-formed.