30 Input/output library [input.output]

30.9 File-based streams [file.streams]

30.9.2 Class template basic_­filebuf [filebuf]

30.9.2.2 Assign and swap [filebuf.assign]

basic_filebuf& operator=(basic_filebuf&& rhs);
Effects: Calls close() then move assigns from rhs.
After the move assignment *this has the observable state it would have had if it had been move constructed from rhs (see [filebuf.cons]).
Returns: *this.
void swap(basic_filebuf& rhs);
Effects: Exchanges the state of *this and rhs.
template<class charT, class traits> void swap(basic_filebuf<charT, traits>& x, basic_filebuf<charT, traits>& y);
Effects: As if by x.swap(y).