std::ctype_byname<char>

 

C++

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Concepts library (C++20)

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Utilities library

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Technical Specifications

 

Localizations library

Locales and facets
locale
use_facet	has_facet
Character classification
isspace isblank (C++11) iscntrl isupper islower isalpha	isdigit ispunct isxdigit isalnum isprint isgraph
Conversions
toupper tolower	wstring_convert (C++11) wbuffer_convert (C++11)
Facet category base classes
ctype_base codecvt_base messages_base	time_base money_base
Facet categories
ctype ctype<char> codecvt collate messages time_get time_put	num_get num_put numpunct money_get money_put moneypunct
Locale-specific facets
ctype_byname codecvt_byname messages_byname collate_byname	time_get_byname time_put_byname numpunct_byname moneypunct_byname
Code conversion facets
codecvt_utf8 (C++11) codecvt_utf16 (C++11)	codecvt_utf8_utf16 (C++11) codecvt_mode (C++11)
C locale
setlocale localeconv lconv	LC_ALLLC_COLLATELC_CTYPELC_MONETARYLC_NUMERICLC_TIME

 

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

This specialization of std::ctype_byname encapsulates character classification features for type char. Like its base class std::ctype<char> and unlike general-purpose std::ctype_byname, table lookup is used to classify characters

Member types

Member type	Definition
mask	ctype<char>::mask

Member functions

(constructor)	constructs a new ctype_byname<char> facet (public member function)
(destructor)	destructs a ctype_byname<char> facet (protected member function)

Inherited from std::ctype<char>

Member types

Member type	Definition
char_type	char

Member objects

Member name	Type
id (static)	std::locale::id
table_size (static const)	std::size_t size of the classification table, at least 256

Member functions

table	obtains the character classification table (public member function of std::ctype<char>)
classic_table [static]	obtains the "C" locale character classification table (public static member function of std::ctype<char>)
is	classifies a character or a character sequence, using the classification table (public member function of std::ctype<char>)
scan_is	locates the first character in a sequence that conforms to given classification, using the classification table (public member function of std::ctype<char>)
scan_not	locates the first character in a sequence that fails given classification, using the classification table (public member function of std::ctype<char>)
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>)

Protected member functions

do_toupper [virtual]	converts a character or characters to uppercase (virtual protected member function of std::ctype<CharT>)
do_tolower [virtual]	converts a character or characters to lowercase (virtual protected member function of std::ctype<CharT>)
do_widen [virtual]	converts a character or characters from char to charT (virtual protected member function of std::ctype<CharT>)
do_narrow [virtual]	converts a character or characters from charT to char (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 [static]	the value of mask identifying whitespace character classification (public static member constant)
print [static]	the value of mask identifying printable character classification (public static member constant)
cntrl [static]	the value of mask identifying control character classification (public static member constant)
upper [static]	the value of mask identifying uppercase character classification (public static member constant)
lower [static]	the value of mask identifying lowercase character classification (public static member constant)
alpha [static]	the value of mask identifying alphabetic character classification (public static member constant)
digit [static]	the value of mask identifying digit character classification (public static member constant)
punct [static]	the value of mask identifying punctuation character classification (public static member constant)
xdigit [static]	the value of mask identifying hexadecimal digit character classification (public static member constant)
blank [static] (C++11)	the value of mask identifying blank character classification (public static member constant)
alnum [static]	alpha | digit (public static member constant)
graph [static]	alnum | punct (public static member constant)

Example

Run this code

#include <iostream>
#include <locale>
 
int main()
{
    char c = '\xde'; // 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<char>("en_US.utf8"));
 
    std::cout << "isupper('Þ', C locale with Unicode ctype<char>) returned "
              << std::boolalpha << std::isupper(c, loc) << '\n';
 
    loc = std::locale(loc, new std::ctype_byname<char>("is_IS.iso88591"));
 
    std::cout << "isupper('Þ', C locale with Islandic ctype<char>) returned "
              << std::boolalpha << std::isupper(c, loc) << '\n';
}

Output:

isupper('Þ', C locale) returned false
isupper('Þ', C locale with Unicode ctype<char>) returned false
isupper('Þ', C locale with Islandic ctype<char>) returned true

See also

ctype	defines character classification tables (class template)
ctype<char>	specialization of std::ctype for type char (class template specialization)