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std::copy_constructible

From cppreference.com
< cpp‎ | concepts
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).

More precisely, if T is an object type, then copy_constructible<T> is satisfied only if given

  • v, a 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;
  • T(v) is equal to v.

[edit] See also

checks if a type has a copy constructor
(class template) [edit]