std::common_with
Defined in header <concepts>
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||
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template
<
class T, class U >
concept common_with =
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(since C++20) | |
The concept common_with<T, U> specifies that two types T and U share a common type (as computed by std::common_type_t
Semantic requirements
T and U model std::common_with<T, U> only if, given equality-preserving expressions t1, t2, u1 and u2 such that decltype((t1)) and decltype((t2)) are both T and decltype((u1)) and decltype((u2)) are both U
-
std::common_type_t
<T, U>
(t1)
equals
std::common_type_t
<T, U>
(t2)
if and only if
t1equalst2 -
std::common_type_t
<T, U>
(u1)
equals
std::common_type_t
<T, U>
(u2)
if and only if
u1equalsu2
In other words, the conversion to the common type must preserve equality.
Equality preservation
Expressions declared in requires expressions of the standard library concepts are required to be equality-preserving
References
- C++23 standard (ISO/IEC 14882:2024):
- 18.4.6 Concept
common_with[concept.common]
- 18.4.6 Concept
- C++20 standard (ISO/IEC 14882:2020):
- 18.4.6 Concept
common_with[concept.common]
- 18.4.6 Concept
See also
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(C++11)
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determines the common type of a group of types (class template) |
| determines the common reference type of a group of types (class template) |
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(C++20)
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specifies that two types share a common reference type (concept) |