29 Input/output library [input.output]

29.9 Span-based streams [span.streams]

29.9.5 Class template basic_­ospanstream [ospanstream] Constructors [ospanstream.ctor]

explicit basic_ospanstream(std::span<charT> s, ios_base::openmode which = ios_base::out);
Effects: Initializes the base class with basic_­ostream<charT, traits>(addressof(sb)) and sb with basic_­spanbuf<charT, traits>(s, which | ios_­base​::​out) ([spanbuf.ctor]).
basic_ospanstream(basic_ospanstream&& rhs) noexcept;
Effects: Initializes the base class with std​::​move(rhs) and sb with std​::​move(rhs.sb).
Next, basic_­ostream<charT, traits>​::​set_­rdbuf(addressof(sb)) is called to install the contained basic_­spanbuf.