30 Input/output library [input.output]

30.9 File-based streams [file.streams]

30.9.3 Class template basic_­ifstream [ifstream]

30.9.3.2 Assign and swap [ifstream.assign]

basic_ifstream& operator=(basic_ifstream&& rhs);
Effects: Move assigns the base and members of *this from the base and corresponding members of rhs.
Returns: *this.
void swap(basic_ifstream& rhs);
Effects: Exchanges the state of *this and rhs by calling basic_­istream<charT, traits>​::​swap(rhs) and sb.swap(rhs.sb).
template <class charT, class traits> void swap(basic_ifstream<charT, traits>& x, basic_ifstream<charT, traits>& y);
Effects: As if by x.swap(y).