Annex D (normative) Compatibility features [depr]

D.27 Deprecated convenience conversion interfaces [depr.conversions]

D.27.3 Class template wbuffer_convert [depr.conversions.buffer]

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.

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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; wbuffer_convert() : wbuffer_convert(nullptr) {} explicit wbuffer_convert(streambuf* bytebuf, 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

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state_type state() const;

Returns: cvtstate.

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streambuf* rdbuf() const;

Returns: bufptr.

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streambuf* rdbuf(streambuf* bytebuf);

Effects: Stores bytebuf in bufptr.

Returns: The previous value of bufptr.

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

Preconditions: pcvt is not null.

Effects: The constructor constructs a stream buffer object, initializes bufptr to bytebuf, initializes cvtptr to pcvt, and initializes cvtstate to state.

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~wbuffer_convert();

Effects: delete cvtptr.