31 Input/output library [input.output]

31.7 Formatting and manipulators [iostream.format]

31.7.5 Output streams [output.streams]

31.7.5.2 Class template basic_­ostream [ostream]

31.7.5.2.3 Assignment and swap [ostream.assign]

basic_ostream& operator=(basic_ostream&& rhs);
Effects: Equivalent to: swap(rhs).
Returns: *this.
void swap(basic_ostream& rhs);
Effects: Calls basic_­ios<charT, traits>​::​swap(rhs).