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