C++ named requirements: UnaryTypeTrait (since C++11)
A UnaryTypeTrait is a class template that describes a property of its template type parameter with an std::integral_constant (typically std::bool_constant) specialization.
Requirements
- DefaultConstructible and CopyConstructible.
- Takes one template type parameter (additional template parameters are optional and allowed).
- Publicly and unambiguously derived from a specialization of
std::integral_constant, known as its base characteristic. - The member names of the base characteristic are not hidden and are unambiguously available.
Standard library
The following type traits all satisfy UnaryTypeTrait:
- Primary type categories
- Composite type categories
- Type properties
- Supported operations
- Property queries
The following standard library class templates also satisfy UnaryTypeTrait.
|
(C++11) | compile-time constant of specified type with specified value (class template) |
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(C++17) | logical NOT metafunction (class template) |
|
(C++11) | obtains the size of a |
|
(C++11) | obtains the size of an array (class template specialization) |
|
(C++11) | obtains the size of a pair (class template specialization) |
|
(C++17) | obtains the size of the variant's list of alternatives at compile time(class template) (variable template) |
|
(C++11) | indicates that an object is std::bind expression or can be used as one (class template) |
|
(C++11) | indicates that an object is a standard placeholder or can be used as one (class template) |
|
(C++17) | test whether a class represents an execution policy (class template) |
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