namespace std {
template<class charT, class traits = char_traits<charT>>
class basic_spanstream
: public basic_iostream<charT, traits> {
public:
using char_type = charT;
using int_type = typename traits::int_type;
using pos_type = typename traits::pos_type;
using off_type = typename traits::off_type;
using traits_type = traits;
explicit basic_spanstream(std::span<charT> s,
ios_base::openmode which = ios_base::out | ios_base::in);
basic_spanstream(const basic_spanstream&) = delete;
basic_spanstream(basic_spanstream&& rhs);
basic_spanstream& operator=(const basic_spanstream&) = delete;
basic_spanstream& operator=(basic_spanstream&& rhs);
void swap(basic_spanstream& rhs);
basic_spanbuf<charT, traits>* rdbuf() const noexcept;
std::span<charT> span() const noexcept;
void span(std::span<charT> s) noexcept;
private:
basic_spanbuf<charT, traits> sb;
};
}