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    std::is_implicit_lifetime

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    Defined in header <type_traits>
    template< class T > struct is_implicit_lifetime;
    		 (since C++23)
    See More

    std::is_implicit_lifetime is a UnaryTypeTrait.

    If T is an implicit-lifetime type, provides the member constant value equal to true. For any other type, value is false.

    The behavior is undefined if T is an incomplete type other than an array type or (possibly cv-qualified) void.

    If the program adds specializations for std::is_implicit_lifetime or std::is_implicit_lifetime_v, the behavior is undefined.

    Template parameters

    T - a type to check

    Helper variable template

    template< class T > constexpr bool is_implicit_lifetime_v = is_implicit_lifetime<T>::value;
    		 (since C++23)
    [edit]

    Inherited from std::integral_constant

    Member constants

    value
    [static]
    		 true if T is an implicit-lifetime type, false otherwise
    (public static member constant)

    Member functions

    operator bool
    		 converts the object to bool, returns value
    (public member function)
    operator()
    (C++14)
    		 returns value
    (public member function)

    Member types

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

    Notes

    Feature-test macro Value Std Feature
    __cpp_lib_is_implicit_lifetime 202302L (C++23) std::is_implicit_lifetime

    Example

    Run this code
    // The following types are collectively called implicit-lifetime types:
// * scalar types:
//     * arithmetic types
//     * enumeration types
//     * pointer types
//     * pointer-to-member types
//     * std::nullptr_t
// * implicit-lifetime class types
//     * is an aggregate whose destructor is not user-provided
//     * has at least one trivial eligible constructor and a trivial,
//       non-deleted destructor
// * array types
// * cv-qualified versions of these types.
#include <type_traits>

static_assert(std::is_implicit_lifetime_v<int>); // arithmetic type is a scalar type
static_assert(std::is_implicit_lifetime_v<const int>); // cv-qualified a scalar type

enum E { e };
static_assert(std::is_implicit_lifetime_v<E>); // enumeration type is a scalar type
static_assert(std::is_implicit_lifetime_v<int*>); // pointer type is a scalar type
static_assert(std::is_implicit_lifetime_v<std::nullptr_t>); // scalar type

struct S { int x, y; };
// S is an implicit-lifetime class: an aggregate without user-provided destructor
static_assert(std::is_implicit_lifetime_v<S>);

static_assert(std::is_implicit_lifetime_v<int S::*>); // pointer-to-member

struct X { ~X() = delete; };
// X is not implicit-lifetime class due to deleted destructor
static_assert(!std::is_implicit_lifetime_v<X>);

static_assert(std::is_implicit_lifetime_v<int[8]>); // array type
static_assert(std::is_implicit_lifetime_v<volatile int[8]>); // cv-qualified array type

int main() {}

    See also

    (C++11)
    		 checks if a type is a scalar type
    (class template) [edit]
    (C++11)
    		 checks if a type is an array type
    (class template) [edit]
    (C++17)
    		 checks if a type is an aggregate type
    (class template) [edit]
    (C++23)
    		 implicitly creates objects in given storage with the object representation reused
    (function template) [edit]