messages facet

Overview

Message catalogs are basically string tables used by the operating systems to store system messages. 

Details

Message catalogs are stored under language specific subdirectories, under msg folder of the Operating system. There various tools such as gentext or gencat to create catalogs.

Topics
messages_base
messages

messages_base

This is a base classes messages facet. It defines the following member inherited by all the derived classes.

int catalog

messages

The messages standard facet is used to read individual strings from a message catalog.

Syntax

template<class CharT> 
class messages:public facet, public message_base

CharT can be char and whcar_t. It's aliased as member char_type.  It represents the type of the characters in the sequence to interpret.

Specializations

//narrow string representations of messages
messages<char>

//wide string representations of messages
messages<wchar_t>	

Fields

Name	Description
locale::id id	the identifier of the facet. Represents the messages category of the facet.

types

Name	Description
char_type	Represents the character type. It's a typedef for CharT .
string_type	Represents string type corresponding to the character type.  It's a typedef for basic_string<charT>

Constructor

Name	Description
messages(size_t refs = 0)	Creates a messages facet and forwards the starting reference count refs to the base class constructor, locale::facet::facet()

Methods

Name	Description
catalog open (const string& name, const locale& loc)	Opens the message catalog by name to access messages and returns an object that uniquely identifies the catalog when calling member messages::get. Returns negative number upon failures.
char_type get (catalog cat, int set, int msgid, const string_type& def )	Retrieves the message identified by set, msgid, and def in the catalog cat. If the message is not found, def is returned.
void close (catalog cat)	Closes the opened catalog identified by cat.
Example