std::is_union
From cppreference.com
Defined in header
<type_traits>
|
||
template< class T >
struct is_union; |
(since C++11) | |
Checks whether T
is an union type. Provides the member constant value
which is equal to true, if T
is an union type . Otherwise, value
is equal to false.
Contents |
[edit] Template parameters
T | - | a type to check |
Inherited from std::integral_constant
Member constants
value
[static]
|
true if T is a union type , false otherwise (public static member constant) |
Member functions
operator bool |
converts the object to bool, returns value (public member function) |
operator()
(C++14)
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returns value (public member function) |
Member types
Type | Definition |
value_type
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bool
|
type
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std::integral_constant<bool, value> |
[edit] Example
Run this code
#include <iostream> #include <type_traits> struct A {}; typedef union { int a; float b; } B; struct C { B d; }; int main() { std::cout << std::boolalpha; std::cout << std::is_union<A>::value << '\n'; std::cout << std::is_union<B>::value << '\n'; std::cout << std::is_union<C>::value << '\n'; std::cout << std::is_union<int>::value << '\n'; }
Output:
false true false false
[edit] See also
(C++11)
|
checks if a type is a class type (but not union type) (class template) |
(library fundamentals TS)
|
variable template alias of std::is_union::value (variable template) |