Annex D (normative) Compatibility features [depr]

Class template wbuffer_­convert looks like a wide stream buffer, but performs all its I/O through an underlying byte stream buffer that you specify when you construct it. Like class template wstring_­convert, it lets you specify a code conversion facet to perform the conversions, without affecting any streams or locales.

namespace std {
  template <class Codecvt, class Elem = wchar_t, class Tr = char_traits<Elem>>
    class wbuffer_convert : public basic_streambuf<Elem, Tr> {
    public:
      using state_type = typename Codecvt::state_type;

      explicit wbuffer_convert(streambuf* bytebuf = 0,
                               Codecvt* pcvt = new Codecvt,
                               state_type state = state_type());

      ~wbuffer_convert();

      wbuffer_convert(const wbuffer_convert&) = delete;
      wbuffer_convert& operator=(const wbuffer_convert&) = delete;

      streambuf* rdbuf() const;
      streambuf* rdbuf(streambuf* bytebuf);

      state_type state() const;

    private:
      streambuf* bufptr;            // exposition only
      Codecvt* cvtptr;              // exposition only
      state_type cvtstate;          // exposition only
  };
}

The class template describes a stream buffer that controls the transmission of elements of type Elem, whose character traits are described by the class Tr, to and from a byte stream buffer of type streambuf. Conversion between a sequence of Elem values and multibyte sequences is performed by an object of class Codecvt, which shall meet the requirements of the standard code-conversion facet codecvt<Elem, char, mbstate_­t>.

An object of this class template stores:

• (3.1)

  bufptr — a pointer to its underlying byte stream buffer

• (3.2)

  cvtptr — a pointer to the allocated conversion object (which is freed when the wbuffer_­convert object is destroyed)

• (3.3)

  cvtstate — a conversion state object