Variable templates for type traits
Utilities » Metaprogramming
Collaboration diagram for Variable templates for type traits:

## Variables

template<typename _Tp>
constexpr bool | std::has_unique_object_representations_v
template<typename _Tp>
constexpr bool | std::is_aggregate_v
template<typename _Tp>
constexpr bool | std::is_bounded_array_v
template<typename _Tp, typename _Up>
constexpr bool | std::is_layout_compatible_v
template<typename _Base, typename _Derived>
constexpr bool | std::is_pointer_interconvertible_base_of_v
template<typename _Tp>
constexpr bool | std::is_unbounded_array_v
template<typename... _Bn>
constexpr bool | std::conjunction_v
template<typename... _Bn>
constexpr bool | std::disjunction_v
template<typename _Pp>
constexpr bool | std::negation_v
template<typename _Tp>
constexpr bool | std::is_void_v
template<typename _Tp>
constexpr bool | std::is_null_pointer_v
template<typename _Tp>
constexpr bool | std::is_integral_v
template<typename _Tp>
constexpr bool | std::is_floating_point_v
template<typename _Tp>
constexpr bool | std::is_array_v
template<typename _Tp>
constexpr bool | std::is_array_v< _Tp[]>
template<typename _Tp, size_t _Num>
constexpr bool | std::is_array_v< _Tp[_Num]>
template<typename _Tp>
constexpr bool | std::is_pointer_v
template<typename _Tp>
constexpr bool | std::is_lvalue_reference_v
template<typename _Tp>
constexpr bool | std::is_lvalue_reference_v< _Tp & >
template<typename _Tp>
constexpr bool | std::is_rvalue_reference_v
template<typename _Tp>
constexpr bool | std::is_rvalue_reference_v< _Tp && >
template<typename _Tp>
constexpr bool | std::is_member_object_pointer_v
template<typename _Tp>
constexpr bool | std::is_member_function_pointer_v
template<typename _Tp>
constexpr bool | std::is_enum_v
template<typename _Tp>
constexpr bool | std::is_union_v
template<typename _Tp>
constexpr bool | std::is_class_v
template<typename _Tp>
constexpr bool | std::is_function_v
template<typename _Tp>
constexpr bool | std::is_reference_v
template<typename _Tp>
constexpr bool | std::is_reference_v< _Tp & >
template<typename _Tp>
constexpr bool | std::is_reference_v< _Tp && >
template<typename _Tp>
constexpr bool | std::is_arithmetic_v
template<typename _Tp>
constexpr bool | std::is_fundamental_v
template<typename _Tp>
constexpr bool | std::is_object_v
template<typename _Tp>
constexpr bool | std::is_scalar_v
template<typename _Tp>
constexpr bool | std::is_compound_v
template<typename _Tp>
constexpr bool | std::is_member_pointer_v
template<typename _Tp>
constexpr bool | std::is_const_v
template<typename _Tp>
constexpr bool | std::is_const_v< const _Tp >
template<typename _Tp>
constexpr bool | std::is_volatile_v
template<typename _Tp>
constexpr bool | std::is_volatile_v< volatile _Tp >
template<typename _Tp>
constexpr bool | std::is_trivial_v
template<typename _Tp>
constexpr bool | std::is_trivially_copyable_v
template<typename _Tp>
constexpr bool | std::is_standard_layout_v
template<typename _Tp>
constexpr bool | std::is_pod_v
template<typename _Tp>
constexpr bool | std::is_literal_type_v
template<typename _Tp>
constexpr bool | std::is_empty_v
template<typename _Tp>
constexpr bool | std::is_polymorphic_v
template<typename _Tp>
constexpr bool | std::is_abstract_v
template<typename _Tp>
constexpr bool | std::is_final_v
template<typename _Tp>
constexpr bool | std::is_signed_v
template<typename _Tp>
constexpr bool | std::is_unsigned_v
template<typename _Tp, typename... _Args>
constexpr bool | std::is_constructible_v
template<typename _Tp>
constexpr bool | std::is_default_constructible_v
template<typename _Tp>
constexpr bool | std::is_copy_constructible_v
template<typename _Tp>
constexpr bool | std::is_move_constructible_v
template<typename _Tp, typename _Up>
constexpr bool | std::is_assignable_v
template<typename _Tp>
constexpr bool | std::is_copy_assignable_v
template<typename _Tp>
constexpr bool | std::is_move_assignable_v
template<typename _Tp>
constexpr bool | std::is_destructible_v
template<typename _Tp, typename... _Args>
constexpr bool | std::is_trivially_constructible_v
template<typename _Tp>
constexpr bool | std::is_trivially_default_constructible_v
template<typename _Tp>
constexpr bool | std::is_trivially_copy_constructible_v
template<typename _Tp>
constexpr bool | std::is_trivially_move_constructible_v
template<typename _Tp, typename _Up>
constexpr bool | std::is_trivially_assignable_v
template<typename _Tp>
constexpr bool | std::is_trivially_copy_assignable_v
template<typename _Tp>
constexpr bool | std::is_trivially_move_assignable_v
template<typename _Tp>
constexpr bool | std::is_trivially_destructible_v
template<typename _Tp, typename... _Args>
constexpr bool | std::is_nothrow_constructible_v
template<typename _Tp>
constexpr bool | std::is_nothrow_default_constructible_v
template<typename _Tp>
constexpr bool | std::is_nothrow_copy_constructible_v
template<typename _Tp>
constexpr bool | std::is_nothrow_move_constructible_v
template<typename _Tp, typename _Up>
constexpr bool | std::is_nothrow_assignable_v
template<typename _Tp>
constexpr bool | std::is_nothrow_copy_assignable_v
template<typename _Tp>
constexpr bool | std::is_nothrow_move_assignable_v
template<typename _Tp>
constexpr bool | std::is_nothrow_destructible_v
template<typename _Tp>
constexpr bool | std::has_virtual_destructor_v
template<typename _Tp>
constexpr size_t | std::alignment_of_v
template<typename _Tp>
constexpr size_t | std::rank_v
template<typename _Tp, size_t _Size>
constexpr size_t | std::rank_v< _Tp[_Size]>
template<typename _Tp>
constexpr size_t | std::rank_v< _Tp[]>
template<typename _Tp, unsigned _Idx = 0>
constexpr size_t | std::extent_v
template<typename _Tp, size_t _Size>
constexpr size_t | std::extent_v< _Tp[_Size], 0 >
template<typename _Tp, unsigned _Idx, size_t _Size>
constexpr size_t | std::extent_v< _Tp[_Size], _Idx >
template<typename _Tp>
constexpr size_t | std::extent_v< _Tp[], 0 >
template<typename _Tp, unsigned _Idx>
constexpr size_t | std::extent_v< _Tp[], _Idx >
template<typename _Tp, typename _Up>
constexpr bool | std::is_same_v
template<typename _Tp>
constexpr bool | std::is_same_v< _Tp, _Tp >
template<typename _Base, typename _Derived>
constexpr bool | std::is_base_of_v
template<typename _From, typename _To>
constexpr bool | std::is_convertible_v
template<typename _Fn, typename... _Args>
constexpr bool | std::is_invocable_v
template<typename _Fn, typename... _Args>
constexpr bool | std::is_nothrow_invocable_v
template<typename _Ret, typename _Fn, typename... _Args>
constexpr bool | std::is_invocable_r_v
template<typename _Ret, typename _Fn, typename... _Args>
constexpr bool | std::is_nothrow_invocable_r_v

## Detailed Description

Each variable is_xxx_v<T> is a boolean constant with the same value as the value member of the corresponding type trait is_xxx<T>.

Since
  C++17 unless noted otherwise.

## Variable Documentation

## alignment_of_v

template<typename _Tp>

size_t std::alignment_of_v

inline constexpr

Definition at line 3333 of file type_traits.

## conjunction_v

template<typename... _Bn>

bool std::conjunction_v

inline constexpr

Definition at line 244 of file type_traits.

## disjunction_v

template<typename... _Bn>

bool std::disjunction_v

inline constexpr

Definition at line 247 of file type_traits.

## extent_v

template<typename _Tp, unsigned _Idx = 0>

size_t std::extent_v

inline constexpr

Definition at line 3343 of file type_traits.

## extent_v< _Tp[], 0 >

template<typename _Tp>

size_t std::extent_v< _Tp[], 0 >

inline constexpr

Definition at line 3349 of file type_traits.

## extent_v< _Tp[], _Idx >

template<typename _Tp, unsigned _Idx>

size_t std::extent_v< _Tp[], _Idx >

inline constexpr

Definition at line 3351 of file type_traits.

## extent_v< _Tp[_Size], 0 >

template<typename _Tp, size_t _Size>

size_t std::extent_v< _Tp[_Size], 0 >

inline constexpr

Definition at line 3345 of file type_traits.

## extent_v< _Tp[_Size], _Idx >

template<typename _Tp, unsigned _Idx, size_t _Size>

size_t std::extent_v< _Tp[_Size], _Idx >

inline constexpr

Definition at line 3347 of file type_traits.

## has_unique_object_representations_v

template<typename _Tp>

bool std::has_unique_object_representations_v

inline constexpr

Definition at line 3400 of file type_traits.

## has_virtual_destructor_v

template<typename _Tp>

bool std::has_virtual_destructor_v

inline constexpr

Definition at line 3329 of file type_traits.

## is_abstract_v

template<typename _Tp>

bool std::is_abstract_v

inline constexpr

Definition at line 3241 of file type_traits.

## is_aggregate_v

template<typename _Tp>

bool std::is_aggregate_v

inline constexpr

is_aggregate_v - true if the type is an aggregate.

Since
  C++17

Definition at line 3418 of file type_traits.

## is_arithmetic_v

template<typename _Tp>

bool std::is_arithmetic_v

inline constexpr

Definition at line 3204 of file type_traits.

## is_array_v

template<typename _Tp>

bool std::is_array_v

inline constexpr

Definition at line 3167 of file type_traits.

## is_array_v< _Tp[]>

template<typename _Tp>

bool std::is_array_v< _Tp[]>

inline constexpr

Definition at line 3169 of file type_traits.

## is_array_v< _Tp[_Num]>

template<typename _Tp, size_t _Num>

bool std::is_array_v< _Tp[_Num]>

inline constexpr

Definition at line 3171 of file type_traits.

## is_assignable_v

template<typename _Tp, typename _Up>

bool std::is_assignable_v

inline constexpr

Definition at line 3262 of file type_traits.

## is_base_of_v

template<typename _Base, typename _Derived>

bool std::is_base_of_v

inline constexpr

Definition at line 3363 of file type_traits.

## is_bounded_array_v

template<typename _Tp>

bool std::is_bounded_array_v

inline constexpr

True for a type that is an array of known bound.

Since
  C++20

Definition at line 3497 of file type_traits.

## is_class_v

template<typename _Tp>

bool std::is_class_v

inline constexpr

Definition at line 3194 of file type_traits.

## is_compound_v

template<typename _Tp>

bool std::is_compound_v

inline constexpr

Definition at line 3212 of file type_traits.

## is_const_v

template<typename _Tp>

bool std::is_const_v

inline constexpr

Definition at line 3216 of file type_traits.

## is_const_v< const _Tp >

template<typename _Tp>

bool std::is_const_v< const _Tp >

inline constexpr

Definition at line 3218 of file type_traits.

## is_constructible_v

template<typename _Tp, typename... _Args>

bool std::is_constructible_v

inline constexpr

Definition at line 3251 of file type_traits.

## is_convertible_v

template<typename _From, typename _To>

bool std::is_convertible_v

inline constexpr

Definition at line 3366 of file type_traits.

## is_copy_assignable_v

template<typename _Tp>

bool std::is_copy_assignable_v

inline constexpr

Definition at line 3264 of file type_traits.

## is_copy_constructible_v

template<typename _Tp>

bool std::is_copy_constructible_v

inline constexpr

Definition at line 3255 of file type_traits.

## is_default_constructible_v

template<typename _Tp>

bool std::is_default_constructible_v

inline constexpr

Definition at line 3253 of file type_traits.

## is_destructible_v

template<typename _Tp>

bool std::is_destructible_v

inline constexpr

Definition at line 3271 of file type_traits.

## is_empty_v

template<typename _Tp>

bool std::is_empty_v

inline constexpr

Definition at line 3237 of file type_traits.

## is_enum_v

template<typename _Tp>

bool std::is_enum_v

inline constexpr

Definition at line 3190 of file type_traits.

## is_final_v

template<typename _Tp>

bool std::is_final_v

inline constexpr

Definition at line 3243 of file type_traits.

## is_floating_point_v

template<typename _Tp>

bool std::is_floating_point_v

inline constexpr

Definition at line 3164 of file type_traits.

## is_function_v

template<typename _Tp>

bool std::is_function_v

inline constexpr

Definition at line 3196 of file type_traits.

## is_fundamental_v

template<typename _Tp>

bool std::is_fundamental_v

inline constexpr

Definition at line 3206 of file type_traits.

## is_integral_v

template<typename _Tp>

bool std::is_integral_v

inline constexpr

Definition at line 3162 of file type_traits.

## is_invocable_r_v

template<typename _Ret, typename _Fn, typename... _Args>

bool std::is_invocable_r_v

inline constexpr

Definition at line 3377 of file type_traits.

## is_invocable_v

template<typename _Fn, typename... _Args>

bool std::is_invocable_v

inline constexpr

Definition at line 3372 of file type_traits.

## is_layout_compatible_v

template<typename _Tp, typename _Up>

bool std::is_layout_compatible_v

constexpr

Since
  C++20

Definition at line 3536 of file type_traits.

## is_literal_type_v

template<typename _Tp>

bool std::is_literal_type_v

inline constexpr

Definition at line 3235 of file type_traits.

## is_lvalue_reference_v

template<typename _Tp>

bool std::is_lvalue_reference_v

inline constexpr

Definition at line 3176 of file type_traits.

## is_lvalue_reference_v< _Tp & >

template<typename _Tp>

bool std::is_lvalue_reference_v< _Tp & >

inline constexpr

Definition at line 3178 of file type_traits.

## is_member_function_pointer_v

template<typename _Tp>

bool std::is_member_function_pointer_v

inline constexpr

Definition at line 3187 of file type_traits.

## is_member_object_pointer_v

template<typename _Tp>

bool std::is_member_object_pointer_v

inline constexpr

Definition at line 3184 of file type_traits.

## is_member_pointer_v

template<typename _Tp>

bool std::is_member_pointer_v

inline constexpr

Definition at line 3214 of file type_traits.

## is_move_assignable_v

template<typename _Tp>

bool std::is_move_assignable_v

inline constexpr

Definition at line 3267 of file type_traits.

## is_move_constructible_v

template<typename _Tp>

bool std::is_move_constructible_v

inline constexpr

Definition at line 3258 of file type_traits.

## is_nothrow_assignable_v

template<typename _Tp, typename _Up>

bool std::is_nothrow_assignable_v

inline constexpr

Definition at line 3314 of file type_traits.

## is_nothrow_constructible_v

template<typename _Tp, typename... _Args>

bool std::is_nothrow_constructible_v

inline constexpr

Definition at line 3301 of file type_traits.

## is_nothrow_copy_assignable_v

template<typename _Tp>

bool std::is_nothrow_copy_assignable_v

inline constexpr

Definition at line 3317 of file type_traits.

## is_nothrow_copy_constructible_v

template<typename _Tp>

bool std::is_nothrow_copy_constructible_v

inline constexpr

Definition at line 3307 of file type_traits.

## is_nothrow_default_constructible_v

template<typename _Tp>

bool std::is_nothrow_default_constructible_v

inline constexpr

Definition at line 3304 of file type_traits.

## is_nothrow_destructible_v

template<typename _Tp>

bool std::is_nothrow_destructible_v

inline constexpr

Definition at line 3325 of file type_traits.

## is_nothrow_invocable_r_v

template<typename _Ret, typename _Fn, typename... _Args>

bool std::is_nothrow_invocable_r_v

inline constexpr

Definition at line 3380 of file type_traits.

## is_nothrow_invocable_v

template<typename _Fn, typename... _Args>

bool std::is_nothrow_invocable_v

inline constexpr

Definition at line 3374 of file type_traits.

## is_nothrow_move_assignable_v

template<typename _Tp>

bool std::is_nothrow_move_assignable_v

inline constexpr

Definition at line 3321 of file type_traits.

## is_nothrow_move_constructible_v

template<typename _Tp>

bool std::is_nothrow_move_constructible_v

inline constexpr

Definition at line 3310 of file type_traits.

## is_null_pointer_v

template<typename _Tp>

bool std::is_null_pointer_v

inline constexpr

Definition at line 3160 of file type_traits.

## is_object_v

template<typename _Tp>

bool std::is_object_v

inline constexpr

Definition at line 3208 of file type_traits.

## is_pod_v

template<typename _Tp>

bool std::is_pod_v

inline constexpr

Definition at line 3232 of file type_traits.

## is_pointer_interconvertible_base_of_v

template<typename _Base, typename _Derived>

bool std::is_pointer_interconvertible_base_of_v

constexpr

Since
  C++20

Definition at line 3561 of file type_traits.

## is_pointer_v

template<typename _Tp>

bool std::is_pointer_v

inline constexpr

Definition at line 3174 of file type_traits.

## is_polymorphic_v

template<typename _Tp>

bool std::is_polymorphic_v

inline constexpr

Definition at line 3239 of file type_traits.

## is_reference_v

template<typename _Tp>

bool std::is_reference_v

inline constexpr

Definition at line 3198 of file type_traits.

## is_reference_v< _Tp & >

template<typename _Tp>

bool std::is_reference_v< _Tp & >

inline constexpr

Definition at line 3200 of file type_traits.

## is_reference_v< _Tp && >

template<typename _Tp>

bool std::is_reference_v< _Tp && >

inline constexpr

Definition at line 3202 of file type_traits.

## is_rvalue_reference_v

template<typename _Tp>

bool std::is_rvalue_reference_v

inline constexpr

Definition at line 3180 of file type_traits.

## is_rvalue_reference_v< _Tp && >

template<typename _Tp>

bool std::is_rvalue_reference_v< _Tp && >

inline constexpr

Definition at line 3182 of file type_traits.

## is_same_v

template<typename _Tp, typename _Up>

bool std::is_same_v

inline constexpr

Definition at line 3358 of file type_traits.

## is_same_v< _Tp, _Tp >

template<typename _Tp>

bool std::is_same_v< _Tp, _Tp >

inline constexpr

Definition at line 3360 of file type_traits.

## is_scalar_v

template<typename _Tp>

bool std::is_scalar_v

inline constexpr

Definition at line 3210 of file type_traits.

## is_signed_v

template<typename _Tp>

bool std::is_signed_v

inline constexpr

Definition at line 3246 of file type_traits.

## is_standard_layout_v

template<typename _Tp>

bool std::is_standard_layout_v

inline constexpr

Definition at line 3229 of file type_traits.

## is_trivial_v

template<typename _Tp>

bool std::is_trivial_v

inline constexpr

Definition at line 3225 of file type_traits.

## is_trivially_assignable_v

template<typename _Tp, typename _Up>

bool std::is_trivially_assignable_v

inline constexpr

Definition at line 3287 of file type_traits.

## is_trivially_constructible_v

template<typename _Tp, typename... _Args>

bool std::is_trivially_constructible_v

inline constexpr

Definition at line 3274 of file type_traits.

## is_trivially_copy_assignable_v

template<typename _Tp>

bool std::is_trivially_copy_assignable_v

inline constexpr

Definition at line 3290 of file type_traits.

## is_trivially_copy_constructible_v

template<typename _Tp>

bool std::is_trivially_copy_constructible_v

inline constexpr

Definition at line 3280 of file type_traits.

## is_trivially_copyable_v

template<typename _Tp>

bool std::is_trivially_copyable_v

inline constexpr

Definition at line 3227 of file type_traits.

## is_trivially_default_constructible_v

template<typename _Tp>

bool std::is_trivially_default_constructible_v

inline constexpr

Definition at line 3277 of file type_traits.

## is_trivially_destructible_v

template<typename _Tp>

bool std::is_trivially_destructible_v

inline constexpr

Definition at line 3298 of file type_traits.

## is_trivially_move_assignable_v

template<typename _Tp>

bool std::is_trivially_move_assignable_v

inline constexpr

Definition at line 3294 of file type_traits.

## is_trivially_move_constructible_v

template<typename _Tp>

bool std::is_trivially_move_constructible_v

inline constexpr

Definition at line 3283 of file type_traits.

## is_unbounded_array_v

template<typename _Tp>

bool std::is_unbounded_array_v

inline constexpr

True for a type that is an array of unknown bound.

Since
  C++20

Definition at line 3506 of file type_traits.

## is_union_v

template<typename _Tp>

bool std::is_union_v

inline constexpr

Definition at line 3192 of file type_traits.

## is_unsigned_v

template<typename _Tp>

bool std::is_unsigned_v

inline constexpr

Definition at line 3248 of file type_traits.

## is_void_v

template<typename _Tp>

bool std::is_void_v

inline constexpr

Definition at line 3158 of file type_traits.

## is_volatile_v

template<typename _Tp>

bool std::is_volatile_v

inline constexpr

Definition at line 3220 of file type_traits.

## is_volatile_v< volatile _Tp >

template<typename _Tp>

bool std::is_volatile_v< volatile _Tp >

inline constexpr

Definition at line 3222 of file type_traits.

## negation_v

template<typename _Pp>

bool std::negation_v

inline constexpr

Definition at line 250 of file type_traits.

## rank_v

template<typename _Tp>

size_t std::rank_v

inline constexpr

Definition at line 3336 of file type_traits.

## rank_v< _Tp[]>

template<typename _Tp>

size_t std::rank_v< _Tp[]>

inline constexpr

Definition at line 3340 of file type_traits.

## rank_v< _Tp[_Size]>

template<typename _Tp, size_t _Size>

size_t std::rank_v< _Tp[_Size]>

inline constexpr

Definition at line 3338 of file type_traits.