explicit basic_ispanstream(std::span<charT> s, ios_base::openmode which = ios_base::in);
basic_ispanstream(basic_ispanstream&& rhs);
template<class ROS> explicit basic_ispanstream(ROS&& s)
void swap(basic_ispanstream& rhs);
template<class charT, class traits>
void swap(basic_ispanstream<charT, traits>& x, basic_ispanstream<charT, traits>& y);
basic_spanbuf<charT, traits>* rdbuf() const noexcept;
std::span<const charT> span() const noexcept;
void span(std::span<charT> s) noexcept;
template<class ROS> void span(ROS&& s) noexcept;