Introduces implementation-defined attributes for types, objects, code, etc. [[
attr]] [[attr1, attr2, attr3(args)]] [[namespace::attr(args)]] alignas_specifier
Explanation
Attributes provide the unified standard syntax for implementation-defined language extensions, such as the GNU and IBM language extensions __attribute__((...)), Microsoft extension __declspec(), etc.
An attribute can be used almost everywhere in the C++ program, and can be applied to almost everything: to types, to v