# std::wbuffer_convert<Codecvt,Elem,Tr>::wbuffer_convert

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< cpp‎ | locale‎ | wbuffer convert

wbuffer_convert() : wbuffer_convert(nullptr) {} | (1) |
explicit wbuffer_convert( std::streambuf * bytebuf, Codecvt* pcvt = new Codecvt, state_type state = state_type() ); | (2) |
wbuffer_convert( const std::wbuffer_convert & ) = delete; | (3) | (since C++14)

Overload | Data members
--- | ---
`bufptr` | `cvtptr` | `cvtstate`
(1) | nullptr | new Codecvt | state_type()
(2) | bytebuf | pcvt | state

2) If pcvt is a null pointer, the behavior is undefined.
3) The copy constructor is deleted, `wbuffer_convert` is not CopyConstructible.

### Parameters

bytebuf | - | pointer to the underlying buffer
pcvt | - | pointer to a standalone (not managed by a locale) facet
state | - | the initial value of the character conversion state

### Example

Run this code

    #include <codecvt>
    #include <iostream>
    #include <locale>
    #include <sstream>

    int main()
    {
        // Wrap a UTF-8 string stream in a UCS4 wbuffer_convert
        std::stringbuf utf8buf("z\u00df\u6c34\U0001f34c");
                           // or "\x7a\xc3\x9f\xe6\xb0\xb4\xf0\x9f\x8d\x8c"
                           // or u8"zß水🍌"
        std::wbuffer_convert<std::codecvt_utf8<wchar_t>> conv_in(&utf8buf);
        std::wistream ucsbuf(&conv_in);
        std::cout << "Reading from a UTF-8 stringbuf via wbuffer_convert: "
                  << std::hex << std::showbase;
        for (wchar_t c; ucsbuf.get(c);)
            std::cout << static_cast<std::wint_t>(c) << ' ';

        // Wrap a UTF-8 aware std::cout in a UCS4 wbuffer_convert to output UCS4
        std::wbuffer_convert<std::codecvt_utf8<wchar_t>> conv_out(std::cout.rdbuf());
        std::wostream out(&conv_out);
        std::cout << "\nSending UCS4 data to std::cout via wbuffer_convert: ";
        out << L"z\u00df\u6c34\U0001f34c\n";
    }

Output:

    Reading from a UTF-8 stringbuf via wbuffer_convert: 0x7a 0xdf 0x6c34 0x1f34c
    Sending UCS4 data to std::cout via wbuffer_convert: zß水🍌

### Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR | Applied to | Behavior as published | Correct behavior
--- | --- | --- | ---
LWG 2175 | C++11 | pcvt could be a null pointer | the behavior is undefined in this case
LWG 2176 | C++11 | constructors accepting single argument were implicit | made explicit
P0935R0 | C++11 | the default constructor was explicit | made implicit

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