std::is_trivial

 

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is_copy_constructible is_trivially_copy_constructible is_nothrow_copy_constructible (C++11) (C++11) (C++11)
is_move_constructible is_trivially_move_constructible is_nothrow_move_constructible (C++11) (C++11) (C++11)
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is_copy_assignable is_trivially_copy_assignable is_nothrow_copy_assignable (C++11) (C++11) (C++11)
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Defined in header <type_traits>
template< class T > struct is_trivial;		(since C++11)

If T is a trivial type (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.

Inherited from std::integral_constant

Member constants

value [static]	true if T is a trivial type , false otherwise (public static member constant)

Member functions

operator bool	converts the object to bool, returns value (public member function)

Member types

Type	Definition
value_type	bool
type	std::integral_constant<bool, value>

Notes

Only objects (including arrays) of trivial type may be created by a call to std::malloc.

Possible implementation

template< class T > struct is_trivial : std::integral_constant< bool, std::is_trivially_copyable<T>::value && std::is_trivially_default_constructible<T>::value > {};

Example

#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

See also

is_trivially_copyable (C++11)	checks if a type is trivially copyable (class template)