[concept.default.init]

# 18 Concepts library [[concepts]](./#concepts)

## 18.4 Language-related concepts [[concepts.lang]](concepts.lang#concept.default.init)

### 18.4.12 Concept default_initializable [concept.default.init]

[🔗](#concept:default_initializable)

`template<class T>
  constexpr bool is-default-initializable = see below;         // exposition only

template<class T>
  concept [default_initializable](#concept:default_initializable "18.4.12 Concept default_­initializable [concept.default.init]") = [constructible_from](concept.constructible#concept:constructible_from "18.4.11 Concept constructible_­from [concept.constructible]")<T> &&
                                  requires { T{}; } &&
                                  is-default-initializable<T>;
`

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/concepts.tex#L780)

For a type T, *is-default-initializable*<T> is true if and only if the variable definitionT t; is well-formed for some invented variable t;
otherwise it is false[.](#1.sentence-1)

Access checking is performed as if in a context unrelated to T[.](#1.sentence-2)

Only the validity of the immediate context of the variable initialization is considered[.](#1.sentence-3)