Difference between revisions of "cpp/concepts/copy constructible"
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Andreas Krug (Talk | contribs) m (a lvalue -> an lvalue) |
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=== Semantic requirements === | === Semantic requirements === | ||
If {{tt|T}} is an object type, then {{tt|copy_constructible<T>}} is modeled only if given | If {{tt|T}} is an object type, then {{tt|copy_constructible<T>}} is modeled only if given | ||
| − | * {{tt|v}}, | + | * {{tt|v}}, an lvalue of type (possibly {{c|const}}) {{tt|T}} or an rvalue of type {{c|const T}}, |
the following are true: | the following are true: | ||
* After the definition {{c|T u {{=}} v;}}, {{tt|u}} is equal to {{tt|v}} and {{tt|v}} is not modified; | * After the definition {{c|T u {{=}} v;}}, {{tt|u}} is equal to {{tt|v}} and {{tt|v}} is not modified; | ||
Revision as of 12:37, 15 January 2023
| Defined in header <concepts>
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| template <class T> concept copy_constructible = |
(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)Tor an rvalue of type const T,
the following are true:
- After the definition T u = v;,
uis equal tovandvis not modified; -
T(v)is equal tovand does not modifyv.
See also
| (C++11)(C++11)(C++11) |
checks if a type has a copy constructor (class template) |
