std::messages

 

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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 ctype_byname<char> 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_ALL LC_COLLATE LC_CTYPE LC_MONETARY LC_NUMERIC LC_TIME

 

std::messages

Member functions

messages::messages

messages::~messages

messages::open messages::do_open

messages::get messages::do_get

messages::close messages::do_close

 

Defined in header <locale>
template< class charT > class messages : public std::locale::facet, public std::messages_base;

Class template std::messages encapsulates retrieval of strings from message catalogs, such as the ones provided by GNU gettext or by POSIX catgets.

Two specializations are provided by the standard library and are implemented by all locale objects created in a C++ program:

Defined in header <locale>
std::messages<char>	accesses narrow string message catalog
std::messages<wchar_t>	accesses wide string message catalog

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

(constructor)	constructs a new messages facet (public member function)
(destructor)	destructs a messages facet (protected member function)
open	invokes do_open (public member function)
get	invokes do_get (public member function)
close	invokes do_close (public member function)

Protected member functions

do_open [virtual]	opens a named message catalog (virtual protected member function)
do_get [virtual]	retrieves a message from an open message catalog (virtual protected member function)
do_close [virtual]	closes a message catalog (virtual protected member function)

Inherited from std::messages_base

Type	Definition
catalog	int

Example

The following example demonstrated retrieval of messages: on a typical GNU/Linux system it reads from /usr/share/locale/de/LC_MESSAGES/sed.mo

#include <iostream>
#include <locale>
 
int main()
{
    std::locale loc("de_DE.utf8");
    std::cout.imbue(loc);
    auto& facet = std::use_facet<std::messages<char>>(loc);
    auto cat = facet.open("sed", loc);
    if(cat < 0 )
        std::cout << "Could not open german \"sed\" message catalog\n";
    else
        std::cout << "\"No match\" in German: "
                  << facet.get(cat, 0, 0, "No match") << '\n'
                  << "\"Memory exhausted\" in German: "
                  << facet.get(cat, 0, 0, "Memory exhausted") << '\n';
    facet.close(cat);
}

Output:

"No match" in German: Keine Übereinstimmung
"Memory exhausted" in German: Speicher erschöpft

See also

messages_base	defines messages catalog type (class template)
messages_byname	creates a messages facet for the named locale (class template)