namespace std {
  class strstream
    : public basic_iostream<char> {
  public:
    // types
    using char_type = char;
    using int_type  = char_traits<char>::int_type;
    using pos_type  = char_traits<char>::pos_type;
    using off_type  = char_traits<char>::off_type;
    // constructors/destructor
    strstream();
    strstream(char* s, int n,
              ios_base::openmode mode = ios_base::in|ios_base::out);
    virtual ~strstream();
    // members
    strstreambuf* rdbuf() const;
    void freeze(bool freezefl = true);
    int pcount() const;
    char* str();
  private:
    strstreambuf sb;  // exposition only
  };
}strstream();
strstream(char* s, int n,
          ios_base::openmode mode = ios_base::in|ios_base::out);