NAME

std::ctype_byname - std::ctype_byname

Synopsis

Defined in header <locale>
template< class CharT >
class ctype_byname : public std::ctype<CharT>;

std::ctype_byname is a std::ctype facet which encapsulates character classification
rules of the locale specified at its construction.

Two specializations are provided by the standard library

Defined in header <locale>
provides narrow character classification. This
std::ctype_byname<char> specialization uses table lookup for character
classification
std::ctype_byname<wchar_t> provides wide character classification

Member types

Member type Definition
mask ctype<CharT>::mask

Member functions

constructor constructs a new ctype_byname facet
(public member function)
destructor destroys a ctype_byname facet
(protected member function)

std::ctype_byname::ctype_byname

explicit ctype_byname( const char* name, std::size_t refs = 0 );
explicit ctype_byname( const std::string& name, std::size_t refs = 0 (since C++11)
);

Constructs a new std::ctype_byname facet for a locale with name.

refs is used for resource management: if refs == 0, the implementation destroys the
facet, when the last std::locale object holding it is destroyed. Otherwise, the
object is not destroyed.

Parameters

name - the name of the locale
refs - the number of references that link to the facet

std::ctype_byname::~ctype_byname

protected:
~ctype_byname();

Destroys the facet.

Inherited from std::ctype<CharT>

Member types

Member type Definition
char_type CharT

Member objects

Member name Type
static std::locale::id id id of the locale
[static] (public static member constant)
if CharT is char, the following member of std::ctype<char> is inherited
static const std::size_t table_size size of the classification table, at least 256
[static] (public static member constant)

Member functions

is invokes do_is
(public member function of std::ctype<CharT>)
scan_is invokes do_scan_is
(public member function of std::ctype<CharT>)
scan_not invokes do_scan_not
(public member function of std::ctype<CharT>)
toupper invokes do_toupper
(public member function of std::ctype<CharT>)
tolower invokes do_tolower
(public member function of std::ctype<CharT>)
widen invokes do_widen
(public member function of std::ctype<CharT>)
narrow invokes do_narrow
(public member function of std::ctype<CharT>)
if CharT is char, the following members of std::ctype<char> are inherited
table obtains the character classification table
(public member function of std::ctype<char>)
classic_table obtains the "C" locale character classification table
[static] (public static member function of std::ctype<char>)

Protected member functions

do_toupper converts a character or characters to uppercase
[virtual] (virtual protected member function of std::ctype<CharT>)
do_tolower converts a character or characters to lowercase
[virtual] (virtual protected member function of std::ctype<CharT>)
do_widen converts a character or characters from char to charT
[virtual] (virtual protected member function of std::ctype<CharT>)
do_narrow converts a character or characters from charT to char
[virtual] (virtual protected member function of std::ctype<CharT>)
if CharT is char, the following members of std::ctype are NOT inherited
do_is classifies a character or a character sequence
[virtual] (virtual protected member function of std::ctype<CharT>)
do_scan_is locates the first character in a sequence that conforms to given
[virtual] classification
(virtual protected member function of std::ctype<CharT>)
do_scan_not locates the first character in a sequence that fails given
[virtual] classification
(virtual protected member function of std::ctype<CharT>)

Inherited from std::ctype_base

Member types

Type Definition
mask unspecified bitmask type (enumeration, integer type, or bitset)

Member constants

space the value of mask identifying whitespace character classification
[static] (public static member constant)
print the value of mask identifying printable character classification
[static] (public static member constant)
cntrl the value of mask identifying control character classification
[static] (public static member constant)
upper the value of mask identifying uppercase character classification
[static] (public static member constant)
lower the value of mask identifying lowercase character classification
[static] (public static member constant)
alpha the value of mask identifying alphabetic character classification
[static] (public static member constant)
digit the value of mask identifying digit character classification
[static] (public static member constant)
punct the value of mask identifying punctuation character classification
[static] (public static member constant)
xdigit the value of mask identifying hexadecimal digit character
[static] classification
(public static member constant)
blank the value of mask identifying blank character classification
[static] (C++11) (public static member constant)
alnum alpha | digit
[static] (public static member constant)
graph alnum | punct
[static] (public static member constant)

Notes

The explicit specialization std::ctype_byname<char> was listed as a separate entry
in the header file <locale> until C++11. it was removed in C++11 as defect #1298,
but it remains a required specialization, just like std::ctype_byname<wchar_t>.

Example

// Run this code

#include <iostream>
#include <locale>

int main()
{
wchar_t c = L'\u00de'; // capital letter thorn

std::locale loc("C");

std::cout << "isupper('Þ', C locale) returned "
<< std::boolalpha << std::isupper(c, loc) << '\n';

loc = std::locale(loc, new std::ctype_byname<wchar_t>("en_US.utf8"));

std::cout << "isupper('Þ', C locale with Unicode ctype) returned "
<< std::boolalpha << std::isupper(c, loc) << '\n';
}

Output:

isupper('Þ', C locale) returned false
isupper('Þ', C locale with Unicode ctype) returned true