9 Declarations [dcl.dcl]

9.12 Attributes [dcl.attr]

9.12.4 Deprecated attribute [dcl.attr.deprecated]

1
#
The attribute-token deprecated can be used to mark names and entities whose use is still allowed, but is discouraged for some reason.
[ Note
:
In particular, deprecated is appropriate for names and entities that are deemed obsolescent or unsafe.
— end note
 ]
It shall appear at most once in each attribute-list.
An attribute-argument-clause may be present and, if present, it shall have the form: 
( string-literal )
[ Note
: The string-literal in the attribute-argument-clause could be used to explain the rationale for deprecation and/or to suggest a replacing entity. — end note
 ]
2
#
The attribute may be applied to the declaration of a class, a typedef-name, a variable, a non-static data member, a function, a namespace, an enumeration, an enumerator, or a template specialization.
3
#
A name or entity declared without the deprecated attribute can later be redeclared with the attribute and vice-versa.
[ Note
:
Thus, an entity initially declared without the attribute can be marked as deprecated by a subsequent redeclaration.
However, after an entity is marked as deprecated, later redeclarations do not un-deprecate the entity.
— end note
 ]
Redeclarations using different forms of the attribute (with or without the attribute-argument-clause or with different attribute-argument-clauses) are allowed.
4
#
Recommended practice: Implementations should use the deprecated attribute to produce a diagnostic message in case the program refers to a name or entity other than to declare it, after a declaration that specifies the attribute.
The diagnostic message should include the text provided within the attribute-argument-clause of any deprecated attribute applied to the name or entity.