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

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

C++ language

 

Declarations

Overview declaration syntax decl-specifier-seq declarator Specifiers typedef inline virtual function specifier explicit function specifier friend constexpr (C++11) consteval (C++20) storage class specifiers classstruct union enum decltype (C++11) auto (C++11) alignas (C++11) constvolatile elaborated type specifier attributes (C++11)

Declarators reference pointer array Block declarations simple-declaration → structured binding declaration (C++17) alias declaration(C++11) namespace alias definition using-declaration using-directive static_assert declaration (C++11) asm-definition opaque enum declaration(C++11) Other declarations namespace definition function declaration class template declaration function template declaration explicit template instantiation(C++11) explicit template specialization linkage specification attribute declaration (C++11) empty declaration

 

Attributes

noreturn‎ (C++11)

carries_dependency (C++11)

deprecated (C++14)

fallthrough (C++17)

nodiscard (C++17)

maybe_unused (C++17)

likelyunlikely (C++20)(C++20)

no_unique_address (C++20)

expectsensuresassert (C++20)(C++20)(C++20)

optimize_for_synchronized (TM TS)

 

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.