std:: copy_constructible

Defined in header <concepts>
template < class T > concept copy_constructible = std:: move_constructible < T > && std:: constructible_from < T, T & > && std:: convertible_to < T & , T > && std:: constructible_from < T, const T & > && std:: convertible_to < const T & , T > && std:: constructible_from < T, const T > && std:: convertible_to < const T, T > ;		(since C++20)

The concept copy_constructible is satisfied if T is an lvalue reference type, or if it is a move_constructible object type where an object of that type can constructed from a (possibly const) lvalue or const rvalue of that type in both direct- and copy-initialization contexts with the usual semantics (a copy is constructed with the source unchanged).

Semantic requirements

If T is an object type, then copy_constructible<T> is modeled only if given

• v , an lvalue of type (possibly const ) T or an rvalue of type const T ,

the following are true:

• After the definition T u = v ; , u is equal to v and v is not modified;
• T ( v ) is equal to v and does not modify v .

References

See also

is_copy_constructible is_trivially_copy_constructible is_nothrow_copy_constructible (C++11) (C++11) (C++11)

checks if a type has a copy constructor (class template)