using byte_string = basic_string<char, char_traits<char>, ByteAlloc>;
size_t converted() const noexcept;
wide_string from_bytes(char byte);
wide_string from_bytes(const char* ptr);
wide_string from_bytes(const byte_string& str);
wide_string from_bytes(const char* first, const char* last);
using int_type = typename wide_string::traits_type::int_type;
state_type state() const;
using state_type = typename Codecvt::state_type;
byte_string to_bytes(Elem wchar);
byte_string to_bytes(const Elem* wptr);
byte_string to_bytes(const wide_string& wstr);
byte_string to_bytes(const Elem* first, const Elem* last);
using wide_string = basic_string<Elem, char_traits<Elem>, WideAlloc>;
explicit wstring_convert(Codecvt* pcvt);
wstring_convert(Codecvt* pcvt, state_type state);
explicit wstring_convert(const byte_string& byte_err,
const wide_string& wide_err = wide_string());
~wstring_convert();
state_type state() const;
streambuf* rdbuf() const;
streambuf* rdbuf(streambuf* bytebuf);
using state_type = typename Codecvt::state_type;
explicit wbuffer_convert(
streambuf* bytebuf,
Codecvt* pcvt = new Codecvt,
state_type state = state_type());
~wbuffer_convert();