std::is_trivial (3) - Linux Manuals

std::is_trivial: std::is_trivial


std::is_trivial - std::is_trivial


Defined in header <type_traits>
template< class T > (since C++11)
struct is_trivial;

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.

Template parameters

T - a type to check

Helper variable template

template< class T > (since C++17)
inline constexpr bool is_trivial_v = is_trivial<T>::value;

Inherited from std::integral_constant

Member constants

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

Member functions

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

operator() returns value
              (public member function)

Member types

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

Possible implementation

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


// 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';



See also

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