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The class template describes an object that can serve as a locale facet to retrieve localized messages from a catalog of internationalized messages for a given locale.
Currently, while the messages class is implemented, there are no messages.
Syntax
template <class CharType>
class messages : public messages_base;
Parameters
CharType
The type used within a program to encode characters in a locale.
Remarks
As with any locale facet, the static object ID has an initial stored value of zero. The first attempt to access its stored value stores a unique positive value in id.
This facet basically opens a catalog of messages defined in the base class messages_base, retrieves the information required, and closes the catalog.
Constructors
| Constructor | Description |
|---|---|
| messages | The message facet constructor function. |
Typedefs
| Type name | Description |
|---|---|
| char_type | A character type that is used display messages. |
| string_type | A type that describes a string of type basic_string containing characters of type CharType. |
Member functions
| Member function | Description |
|---|---|
| close | Closes the message catalog. |
| do_close | A virtual function called to lose the message catalog. |
| do_get | A virtual function called to retrieve the message catalog. |
| do_open | A virtual function called to open the message catalog. |
| get | Retrieves the message catalog. |
| open | Opens the message catalog. |
Requirements
Header: <locale>
Namespace: std
messages::char_type
A character type that is used display messages.
typedef CharType char_type;
Remarks
The type is a synonym for the template parameter CharType.
messages::close
Closes the message catalog.
void close(catalog _Catval) const;
Parameters
_Catval
The catalog to be closed.
Remarks
The member function calls do_close(_ Catval).
messages::do_close
A virtual function called to lose the message catalog.
virtual void do_close(catalog _Catval) const;
Parameters
_Catval
The catalog to be closed.
Remarks
The protected member function closes the message catalog _Catval, which must have been opened by an earlier call to do_open.
_Catval must be obtained from a previously opened catalog that is not closed.
Example
See the example for close, which calls do_close.
messages::do_get
A virtual function called to retrieve the message catalog.
virtual string_type do_get(
catalog _Catval,
int _Set,
int _Message,
const string_type& _Dfault) const;
Parameters
_Catval
The identification value specifying the message catalog to be searched.
_Set
The first identified used to locate a message in a message catalog.
_Message
The second identified used to locate a message in a message catalog.
_Dfault
The string to be returned on failure.
Return Value
It returns a copy of _Dfault on failure. Otherwise, it returns a copy of the specified message sequence.
Remarks
The protected member function tries to obtain a message sequence from the message catalog _Catval. It may make use of _Set, _Message, and _Dfault in doing so.
Example
See the example for get, which calls do_get.
messages::do_open
A virtual function called to open the message catalog.
virtual catalog do_open(
const string& _Catname,
const locale& _Loc) const;
Parameters
_Catname
The name of the catalog to be searched.
_Loc
The locale being searched for in the catalog.
Return Value
It returns a value that compares less than zero on failure. Otherwise, the returned value can be used as the first argument on a later call to get.
Remarks
The protected member function tries to open a message catalog whose name is _Catname. It may make use of the locale _Loc in doing so
The return value should be used as the argument on a later call to close.
Example
See the example for open, which calls do_open.
messages::get
Retrieves the message catalog.
string_type get(
catalog _CatVal,
int _Set,
int _Message,
const string_type& _Dfault) const;
Parameters
_Catval
The identification value specifying the message catalog to be searched.
_Set
The first identified used to locate a message in a message catalog.
_Message
The second identified used to locate a message in a message catalog.
_Dfault
The string to be returned on failure.
Return Value
It returns a copy of _Dfault on failure. Otherwise, it returns a copy of the specified message sequence.
Remarks
The member function returns do_get(_Catval, _Set, _Message, _Dfault).
messages::messages
The message facet constructor function.
explicit messages(
size_t _Refs = 0);
protected: messages(
const char* _Locname,
size_t _Refs = 0);
Parameters
_Refs
Integer value used to specify the type of memory management for the object.
_Locname
The name of the locale.
Remarks
The possible values for the _Refs parameter and their significance are:
0: The lifetime of the object is managed by the locales that contain it.
1: The lifetime of the object must be manually managed.
> 1: These values are not defined.
No direct examples are possible, because the destructor is protected.
The constructor initializes its base object with locale::facet(_Refs).
messages::open
Opens the message catalog.
catalog open(
const string& _Catname,
const locale& _Loc) const;
Parameters
_Catname
The name of the catalog to be searched.
_Loc
The locale being searched for in the catalog.
Return Value
It returns a value that compares less than zero on failure. Otherwise, the returned value can be used as the first argument on a later call to get.
Remarks
The member function returns do_open(_Catname, _Loc).
messages::string_type
A type that describes a string of type basic_string containing characters of type CharType.
typedef basic_string<CharType, Traits, Allocator> string_type;
Remarks
The type describes a specialization of class template basic_string whose objects can store copies of the message sequences.
See also
<locale>
messages_base Class
Thread Safety in the C++ Standard Library