std::is_trivial

From cppreference.com

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>

[edit] Notes

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

[edit] 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 
> {};

[edit] Example

run this code

#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

[edit] See also


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

Language
Standard library headers
Concepts
Utilities library
Strings library
Containers library
Algorithms library
Iterators library
Numerics library
Input/output library
Localizations library
Regular expressions library (C++11)
Atomic operations library (C++11)
Thread support library (C++11)