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std::is_trivial(3) C++ Standard Libary std::is_trivial(3)


std::is_trivial - std::is_trivial


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

std::is_trivial is a UnaryTypeTrait.

If T is a trivial type, provides the member constant value equal to true. For any
other type, value is false.

If std::remove_all_extents_t<T> is an incomplete type and not (possibly
cv-qualified) void, the behavior is undefined.

If the program adds specializations for std::is_trivial or std::is_trivial_v, the
behavior 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>


// Run this code

#include <type_traits>

struct A { int m; };
static_assert(std::is_trivial_v<A> == true);

struct B { B() {} };
static_assert(std::is_trivial_v<B> == false);

int main() {}

Defect reports

The following behavior-changing defect reports were applied retroactively to
previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 2015 C++11 T could be an array of incomplete the behavior is
class type with unknown bound undefined in this case

See also

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