std::ctype_byname
| Defined in header <locale>
|
||
| template< class CharT > class ctype_byname : public std::ctype<CharT>; |
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std::ctype_byname is a std::ctype facet which encapsulates character classification rules of the locale specified at its construction.
Specializations
The standard library is guaranteed to provide the following specializations:
| Defined in header
<locale> | |
| std::ctype_byname<char> | provides narrow character classification (uses table lookup for character classification) |
| std::ctype_byname<wchar_t> | provides wide character classification |
Nested types
| Type | Definition |
mask
|
typename std::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> (only if CharT is not char)
Nested types
| Type | Definition |
char_type
|
CharT
|
Data members
| Member | Description |
std::locale::id id [static]
|
the identifier of the facet |
Member functions
invokes do_is (public member function of std::ctype<CharT>) | |
invokes do_scan_is (public member function of std::ctype<CharT>) | |
invokes do_scan_not (public member function of std::ctype<CharT>) | |
invokes do_toupper (public member function of std::ctype<CharT>) | |
invokes do_tolower (public member function of std::ctype<CharT>) | |
invokes do_widen (public member function of std::ctype<CharT>) | |
invokes do_narrow (public member function of std::ctype<CharT>) |
Protected member functions
| [virtual] |
converts a character or characters to uppercase (virtual protected member function of std::ctype<CharT>) |
| [virtual] |
converts a character or characters to lowercase (virtual protected member function of std::ctype<CharT>) |
| [virtual] |
converts a character or characters from char to CharT (virtual protected member function of std::ctype<CharT>) |
| [virtual] |
converts a character or characters from CharT to char (virtual protected member function of std::ctype<CharT>) |
| [virtual] |
classifies a character or a character sequence (virtual protected member function of std::ctype<CharT>) |
| [virtual] |
locates the first character in a sequence that conforms to given classification (virtual protected member function of std::ctype<CharT>) |
| [virtual] |
locates the first character in a sequence that fails given classification (virtual protected member function of std::ctype<CharT>) |
Inherited from std::ctype<char> (only if CharT is char)
Nested types
| Type | Definition |
char_type
|
char |
Data members
| Member | Description |
std::locale::id id [static]
|
the identifier of the facet |
const std::size_t table_size [static]
|
size of the classification table, at least 256 |
Member functions
| obtains the character classification table (public member function of std::ctype<char>) | |
| [static] |
obtains the "C" locale character classification table (public static member function of std::ctype<char>) |
| classifies a character or a character sequence, using the classification table (public member function of std::ctype<char>) | |
| locates the first character in a sequence that conforms to given classification, using the classification table (public member function of std::ctype<char>) | |
| locates the first character in a sequence that fails given classification, using the classification table (public member function of std::ctype<char>) | |
invokes do_toupper (public member function of std::ctype<CharT>) | |
invokes do_tolower (public member function of std::ctype<CharT>) | |
invokes do_widen (public member function of std::ctype<CharT>) | |
invokes do_narrow (public member function of std::ctype<CharT>) |
Protected member functions
| [virtual] |
converts a character or characters to uppercase (virtual protected member function of std::ctype<CharT>) |
| [virtual] |
converts a character or characters to lowercase (virtual protected member function of std::ctype<CharT>) |
| [virtual] |
converts a character or characters from char to CharT (virtual protected member function of std::ctype<CharT>) |
| [virtual] |
converts a character or characters from CharT to char (virtual protected member function of std::ctype<CharT>) |
Inherited from std::ctype_base
Nested types
| Type | Definition |
mask
|
unspecified BitmaskType 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) |
Notes
std::ctype_byname<char> was incorrectly declared as an explicit specialization in the synopsis of <locale>, and the declaration was removed by the resolution of LWG issue 1298, but it remains a required specialization, just like std::ctype_byname<wchar_t>.
Example
#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 trueDefect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 16 | C++98 | the definition of the explicit specialization std::ctype_byname<char> misspecified the name and parameter list of do_narrow
|
corrected |
| LWG 616 | C++98 | the typename disambiguator was missing in the definition of mask
|
added |
See also
| defines character classification tables (class template) | |
| specialization of std::ctype for type char (class template specialization) |