Reference

C library:
- <cassert> (assert.h)
- <cctype> (ctype.h)
- <cerrno> (errno.h)
- C++11
  <cfenv> (fenv.h)
- <cfloat> (float.h)
- C++11
  <cinttypes> (inttypes.h)
- <ciso646> (iso646.h)
- <climits> (limits.h)
- <clocale> (locale.h)
- <cmath> (math.h)
- <csetjmp> (setjmp.h)
- <csignal> (signal.h)
- <cstdarg> (stdarg.h)
- C++11
  <cstdbool> (stdbool.h)
- <cstddef> (stddef.h)
- C++11
  <cstdint> (stdint.h)
- <cstdio> (stdio.h)
- <cstdlib> (stdlib.h)
- <cstring> (string.h)
- C++11
  <ctgmath> (tgmath.h)
- <ctime> (time.h)
- C++11
  <cuchar> (uchar.h)
- <cwchar> (wchar.h)
- <cwctype> (wctype.h)
Containers:
- C++11
  <array>
- <deque>
- C++11
  <forward_list>
- <list>
- <map>
- <queue>
- <set>
- <stack>
- C++11
  <unordered_map>
- C++11
  <unordered_set>
- <vector>
Input/Output:
- <fstream>
- <iomanip>
- <ios>
- <iosfwd>
- <iostream>
- <istream>
- <ostream>
- <sstream>
- <streambuf>
Multi-threading:
- C++11
  <atomic>
- C++11
  <condition_variable>
- C++11
  <future>
- C++11
  <mutex>
- C++11
  <thread>
Other:
- <algorithm>
- <bitset>
- C++11
  <chrono>
- C++11
  <codecvt>
- <complex>
- <exception>
- <functional>
- C++11
  <initializer_list>
- <iterator>
- <limits>
- <locale>
- <memory>
- <new>
- <numeric>
- C++11
  <random>
- C++11
  <ratio>
- C++11
  <regex>
- <stdexcept>
- <string>
- C++11
  <system_error>
- C++11
  <tuple>
- C++11
  <type_traits>
- C++11
  <typeindex>
- <typeinfo>
- <utility>
- <valarray>

<locale>

has_facet
locale
use_facet
C++11
wbuffer_convert
C++11
wstring_convert
functions
- isalnum
- isalpha
- C++11
  isblank
- iscntrl
- isdigit
- isgraph
- islower
- isprint
- ispunct
- isspace
- isupper
- isxdigit
- tolower
- toupper
standard facets
- codecvt
- codecvt_base
- codecvt_byname
- collate
- collate_byname
- ctype
- ctype_base
- ctype_byname
- messages
- messages_base
- messages_byname
- money_base
- money_get
- money_put
- moneypunct
- moneypunct_byname
- num_get
- num_put
- numpunct
- numpunct_byname
- time_base
- time_get
- time_get_byname
- time_put
- time_put_byname

std::codecvt

template <class internT, class externT, class stateT> class codecvt;

Convert codeset facet

locale::facet codecvt_base
codecvt

The codecvt standard facet translates between two different character encodings: an internal character type (generally some type of wide character) and an external character type (generally representing a multibyte sequence).

The codecvt class template has a protected destructor: Programs shall only construct objects of derived classes, or use those installed in locale objects (through use_facet ).

All standard locale objects support at least the following facet instantiations of the codecvt class template (as part of the ctype category):

facets in `locale` objects	description
`codecvt<char,char,mbstate_t>`	performs no conversion
`codecvt<wchar_t,char,mbstate_t>`	converts between native wide and narrow character sets

facets in `locale` objects	description
`codecvt<char,char,mbstate_t>`	performs no conversion
`codecvt<wchar_t,char,mbstate_t>`	converts between native wide and narrow character sets
`codecvt<char16_t,char,mbstate_t>`	converts between UTF16 and UTF8 encodings
`codecvt<char32_t,char,mbstate_t>`	converts between UTF32 and UTF8 encodings

Header <codecvt> defines additional stand-alone facet objects derived from codecvt (for more info, see header <codecvt> ).

Template parameters

internT: Internal character type: Typically, this is the wide character type.
Aliased as member intern_type.
externT: External character type: Typically, this is the multi-byte type.
Aliased as member extern_type.
stateT: A state type: Typically, this is an object able to keep track of the state of the conversion, such as mbstate_t (or, more generically, char_traits<externT>::state_type).
Aliased as member state_type.

Member types

member type	definition	description
`intern_type`	The first template parameter (`internT`)	Internal character type
`extern_type`	The second template parameter (`externT`)	External character type
`state_type`	The third template parameter (`stateT`)	State type

The class also inherits codecvt_base::result , which is used as the return type for members in , out and unshift .

Member constants

The following member constants are inherited from codecvt_base (as labels of enum type codecvt_base::result ); They are used as return values by certain member functions.

member constant	type	value	description
`ok`	`codecvt_base::result`	`0`	Conversion successful
`partial`	`codecvt_base::result`	`1`	Partial conversion
`error`	`codecvt_base::result`	`2`	Conversion error
`noconv`	`codecvt_base::result`	`3`	No conversion

The class also contains a public static constant of type locale::id , that uniquely identifies facets with codecvt semantics.

Public member functions

(constructor): codecvt constructor (public member function)

Conversion functions

in: Translate in characters (public member function)

out: Translate out characters (public member function)

unshift: Unshift translation state (public member function)

Character encoding properties

always_noconv: Return noconv characteristics (public member function)

encoding: Return encoding width (public member function)

length: Return length of translated sequence (public member function)

max_length: Return max length of one character (public member function)

Virtual protected member functions

The class defines the virtual protected members which implement the behavior by default of their respective public member functions:

do_always_noconv: Return noconv characteristics [virtual] (protected virtual member function)

do_encoding: Return encoding width [virtual] (protected virtual member function)

do_in: Translate in characters [virtual] (protected virtual member function)

do_length: Return length of translated sequence [virtual] (public member function)

do_max_length: Return max length of one character [virtual] (protected virtual member function)

do_out: Translate out characters [virtual] (protected virtual member function)

do_unshift: Unshift translation state [virtual] (protected virtual member function)

Along with the class destructor:

(destructor): codecvt destructor (protected member function)

The class contains a public static constant of type locale::id that uniquely identifies facets with codecvt semantics.

Specializations

At least the following specializations of this template are provided in all library implementations:

specialization
`codecvt<char,char,mbstate_t>`
`codecvt<wchar_t,char,mbstate_t>`

specialization
`codecvt<char,char,mbstate_t>`
`codecvt<wchar_t,char,mbstate_t>`
`codecvt<char16_t,char,mbstate_t>`
`codecvt<char32_t,char,mbstate_t>`

functions

standard facets

public member functions

protected members