std::messages_byname

 

C++

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Freestanding and hosted

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Named requirements

Feature test macros (C++20)

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Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

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Strings library

Containers library

Iterators library

Ranges 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

 

Defined in header <locale>
template< class CharT > class messages_byname : public std::messages<CharT>;

std::messages_byname is a std::messages facet which encapsulates retrieval of strings from message catalogs of the locale specified at its construction.

Specializations

The standard library is guaranteed to provide the following specializations:

Defined in header <locale>
std::messages_byname<char>	narrow/multibyte message catalog access
std::messages_byname<wchar_t>	wide string message catalog access

Member types

Member type	Definition
catalog	std::messages_base<CharT>::catalog
string_type	std::basic_string<CharT>

Member functions

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

std::messages_byname::messages_byname

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

Constructs a new std::messages_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::messages_byname::~messages_byname

protected: ~messages_byname();

Destroys the facet.

Inherited from std::messages

Member types

Member type	Definition
char_type	CharT
string_type	std::basic_string<CharT>

Member objects

Member name	Type
id (static)	std::locale::id

Member functions

open	invokes do_open (public member function of std::messages<CharT>)
get	invokes do_get (public member function of std::messages<CharT>)
close	invokes do_close (public member function of std::messages<CharT>)

Protected member functions

do_open [virtual]	opens a named message catalog (virtual protected member function of std::messages<CharT>)
do_get [virtual]	retrieves a message from an open message catalog (virtual protected member function of std::messages<CharT>)
do_close [virtual]	closes a message catalog (virtual protected member function of std::messages<CharT>)

Example

Run this code

#include <iostream>
#include <locale>
 
void try_with(const std::locale& loc)
{
    const std::messages<char>& facet = std::use_facet<std::messages<char>>(loc);
 
    std::messages<char>::catalog cat = facet.open("sed", std::cout.getloc());
    if (cat < 0)
        std::cout << "Could not open \"sed\" message catalog\n";
    else
        std::cout << "\"No match\" "
                  << facet.get(cat, 0, 0, "No match") << '\n'
                  << "\"Memory exhausted\" " 
                  << facet.get(cat, 0, 0, "Memory exhausted") << '\n';
 
    facet.close(cat);
}
 
int main()
{
    std::locale loc("en_US.utf8");
    std::cout.imbue(loc);
 
    try_with(std::locale(loc, new std::messages_byname<char>("de_DE.utf8")));
    try_with(std::locale(loc, new std::messages_byname<char>("fr_FR.utf8")));
    try_with(std::locale(loc, new std::messages_byname<char>("ja_JP.utf8")));
}

Possible output:

"No match" Keine Übereinstimmung
"Memory exhausted" Speicher erschöpft
"No match" Pas de concordance
"Memory exhausted" Mémoire épuisée
"No match" 照合しません
"Memory exhausted" メモリーが足りません

See also

messages

implements retrieval of strings from message catalogs (class template)