std::default_initializable - cppreference.com (original) (raw)
| | | | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | ------------- | | template< class T > concept default_initializable = std::constructible_from<T> && requires { T{}; } && /* T t; is well-formed, see below */; | | (since C++20) |
The default_initializable concept checks whether variables of type T can be
- value-initialized (i.e., whether T() is well-formed);
- direct-list-initialized from an empty initializer list (i.e., whether T{} is well-formed); and
- default-initialized (i.e., whether T t; is well-formed).
Access checking is performed as if in a context unrelated to T. Only the validity of the immediate context of the variable initialization is considered.
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[edit] References
C++23 standard (ISO/IEC 14882:2024):
18.4.12 Concept
default_initializable[concept.default.init]C++20 standard (ISO/IEC 14882:2020):
18.4.12 Concept
default_initializable[concept.default.init]