std::wstring_convert

 

C++

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Freestanding and hosted

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Feature test macros (C++20)

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Concepts library (C++20)

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Technical specifications

Symbols index

External libraries

 

Localization library

Locales and facets
Locales
has_facet use_facet	locale
Facet category base classes
ctype_base codecvt_base messages_base	time_base money_base
ctype facets
ctype ctype<char> ctype_byname	codecvt codecvt_byname
numeric facets
num_get num_put	numpunct numpunct_byname
collate facets
collate	collate_byname
time facets
time_get time_put	time_get_byname time_put_byname
monetary facets
money_get money_put	moneypunct moneypunct_byname
messages facets
messages	messages_byname

Character classification and conversion
Character classification
isspace isblank (C++11) iscntrl	isupper islower isalpha	ispunct isdigit isxdigit	isalnum isprint isgraph

Character conversions

toupper

tolower

String and stream conversions

wstring_convert (C++11/17/26*)

wbuffer_convert (C++11/17/26*)

Text encoding identifications

text_encoding (C++26)

Unicode conversion facets

codecvt_utf8 (C++11/17/26*)

codecvt_utf16 (C++11/17/26*)

codecvt_utf8_utf16 (C++11/17/26*)

codecvt_mode (C++11/17/26*)

C library locales
LC_ALLLC_COLLATELC_CTYPELC_MONETARYLC_NUMERICLC_TIME	setlocale localeconv lconv

 

std::wstring_convert

Member functions

wstring_convert::wstring_convert

wstring_convert::~wstring_convert

wstring_convert::from_bytes

wstring_convert::to_bytes

wstring_convert::converted

wstring_convert::state

 

Defined in header <locale>
template<     class Codecvt,     class Elem = wchar_t,     class Wide_alloc = std::allocator<Elem>,     class Byte_alloc = std::allocator<char> > class wstring_convert;		(since C++11) (deprecated in C++17) (removed in C++26)

Class template std::wstring_convert performs conversions between byte string std::string and wide string std::basic_string<Elem>, using an individual code conversion facet Codecvt. std::wstring_convert assumes ownership of the conversion facet, and cannot use a facet managed by a locale.

The standard facets suitable for use with std::wstring_convert are std::codecvt_utf8 for UTF-8/UCS-2 and UTF-8/UCS-4 conversions and std::codecvt_utf8_utf16 for UTF-8/UTF-16 conversions.

Nested types

Type	Definition
byte_string	std::basic_string<char, std::char_traits<char>, Byte_alloc>
wide_string	std::basic_string<Elem, std::char_traits<Elem>, Wide_alloc>
state_type	typename Codecvt::state_type
int_type	typename wide_string::traits_type::int_type

Data members

Member	Description
byte_string byte_err_string	the byte string to display on errors (exposition-only member object*)
wide_string wide_err_string	the wide string to display on errors (exposition-only member object*)
Codecvt* cvtptr	a pointer to the allocated conversion object (exposition-only member object*)
state_type cvtstate	the conversion state object (exposition-only member object*)
std::size_t cvtcount	the conversion count (exposition-only member object*)

Member functions

(constructor)	constructs a new wstring_convert (public member function)
operator=	the copy assignment operator is deleted (public member function)
(destructor)	destructs the wstring_convert and its conversion facet (public member function)
from_bytes	converts a byte string into a wide string (public member function)
to_bytes	converts a wide string into a byte string (public member function)
converted	returns the number of characters successfully converted (public member function)
state	returns the current conversion state (public member function)

See also

Character conversions	locale-defined multibyte (UTF-8, GB18030)	UTF-8	UTF-16
UTF-16	mbrtoc16 / c16rtomb (with C11's DR488)	codecvt<char16_t,char,mbstate_t> codecvt_utf8_utf16<char16_t> codecvt_utf8_utf16<char32_t> codecvt_utf8_utf16<wchar_t>	N/A
UCS-2	c16rtomb (without C11's DR488)	codecvt_utf8<char16_t>	codecvt_utf16<char16_t>
UTF-32	mbrtoc32 / c32rtomb	codecvt<char32_t,char,mbstate_t> codecvt_utf8<char32_t>	codecvt_utf16<char32_t>
system wchar_t: UTF-32 (non-Windows) UCS-2 (Windows)	mbsrtowcs / wcsrtombs use_facet<codecvt <wchar_t,char,mbstate_t>>(locale)	codecvt_utf8<wchar_t>	codecvt_utf16<wchar_t>

wbuffer_convert (C++11)(deprecated in C++17)(removed in C++26)	performs conversion between a byte stream buffer and a wide stream buffer (class template)
codecvt_utf8 (C++11)(deprecated in C++17)(removed in C++26)	converts between UTF-8 and UCS-2/UCS-4 (class template)
codecvt_utf8_utf16 (C++11)(deprecated in C++17)(removed in C++26)	converts between UTF-8 and UTF-16 (class template)