C++ attribute: deprecated (since C++14)

Indicates that the name or entity declared with this attribute is deprecated, that is, the use is allowed, but discouraged for some reason.

Syntax

[[deprecated]]	(1)
[[deprecated( string-literal )]]	(2)

string-literal

-

text that could be used to explain the rationale for deprecation and/or to suggest a replacing entity

Explanation

Indicates that the use of the name or entity declared with this attribute is allowed, but discouraged for some reason. Compilers typically issue warnings on such uses. The string-literal, if specified, is usually included in the warnings.

This attribute is allowed in declarations of the following names or entities:

• class/struct/union: struct [[deprecated]] S;,
• typedef-name, including those declared by alias declaration: [[deprecated]] typedef S* PS;, using PS [[deprecated]] = S*;,
• variable, including static data member: [[deprecated]] int x;,
• non-static data member: union U { [[deprecated]] int n; };,
• function: [[deprecated]] void f();,
• namespace: namespace [[deprecated]] NS { int x; }
• enumeration: enum [[deprecated]] E {};,
• enumerator: enum { A [[deprecated]], B [[deprecated]] = 42 };.
• template specialization: template<> struct [[deprecated]] X<int> {};

A name declared non-deprecated may be redeclared deprecated. A name declared deprecated cannot be un-deprecated by redeclaring it without this attribute.

Example