30 Input/output library [input.output]

30.9 File-based streams [file.streams]

30.9.4 Class template basic_­ofstream [ofstream]

30.9.4.1 basic_­ofstream constructors [ofstream.cons]

basic_ofstream();
Effects: Constructs an object of class basic_­ofstream<charT, traits>, initializing the base class with basic_­ostream<charT, traits>(&sb) ([ostream.cons]) and initializing sb with basic_­filebuf<charT, traits>()) ([filebuf.cons]).
explicit basic_ofstream(const char* s, ios_base::openmode mode = ios_base::out); explicit basic_ofstream(const filesystem::path::value_type* s, ios_base::openmode mode = ios_base::out); // wide systems only; see [fstream.syn]
Effects: Constructs an object of class basic_­ofstream<charT, traits>, initializing the base class with basic_­ostream<charT, traits>(&sb) ([ostream.cons]) and initializing sb with basic_­filebuf<charT, traits>()) ([filebuf.cons]), then calls rdbuf()->open(s, mode | ios_­base​::​out).
If that function returns a null pointer, calls setstate(​failbit).
explicit basic_ofstream(const string& s, ios_base::openmode mode = ios_base::out); explicit basic_ofstream(const filesystem::path& s, ios_base::openmode mode = ios_base::out);
Effects: The same as basic_­ofstream(s.c_­str(), mode).
basic_ofstream(basic_ofstream&& rhs);
Effects: Move constructs from the rvalue rhs.
This is accomplished by move constructing the base class, and the contained basic_­filebuf.
Next basic_­ostream<charT, traits>​::​set_­rdbuf(&sb) is called to install the contained basic_­filebuf.