NAME¶

std::is_trivial - std::is_trivial

Synopsis¶

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

If T is a trivial type, provides the member constant value equal to 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.

The behavior of a program that adds specializations for is_trivial
or is_trivial_v
(since C++17) is undefined.

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
[static] (public static member constant)

Member functions¶

operator bool converts the object to bool, returns value
(public member function)
operator() returns value
(C++14) (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<
bool,
std::is_trivially_copyable<T>::value &&
std::is_trivially_default_constructible<T>::value
> {};

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

See also¶

is_trivially_copyable checks if a type is trivially copyable
(C++11) (class template)
is_default_constructible
is_trivially_default_constructible
is_nothrow_default_constructible checks if a type has a default constructor
(C++11) (class template)
(C++11)
(C++11)