Defined in header <type_traits> | ||
---|---|---|
template< class T > struct is_trivial; | (since C++11) |
If T
is TrivialType (that is, a scalar type, a trivially copyable class with a trivial default constructor, or array of such type/class, possibly cv-qualified), provides the member constant value
equal true
. For any other type, value
is false
.
The behavior is undefined if std::remove_all_extents_t<T>
is an incomplete type and not (possibly cv-qualified) void
.
T | - | a type to check |
template< class T > inline constexpr bool is_trivial_v = is_trivial<T>::value; | (since C++17) |
value
[static] | true if T is a trivial type , false otherwise (public static member constant) |
operator bool | converts the object to bool , returns value (public member function) |
operator()
(C++14) | returns value (public member function) |
Type | Definition |
---|---|
value_type | bool |
type | std::integral_constant<bool, value> |
template< class T > struct is_trivial : std::integral_constant< bool, std::is_trivially_copyable<T>::value && std::is_trivially_default_constructible<T>::value > {}; |
#include <iostream> #include <type_traits> struct A { int m; }; struct B { B() {} }; int main() { std::cout << std::boolalpha; std::cout << std::is_trivial<A>::value << '\n'; std::cout << std::is_trivial<B>::value << '\n'; }
Output:
true false
(C++11) | checks if a type is trivially copyable (class template) |
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