std::is_fundamental

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Feature test macros(C++20)
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Containers library
Iterators library
Ranges library(C++20)
Algorithms library
Strings library
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Date and time library
Input/output library
Filesystem library(C++17)
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Metaprogramming library

Type traits

Type categories

is_void

(C++11)

is_null_pointer

(C++11)(DR*)

is_array (C++11)
is_pointer (C++11)
is_enum (C++11)
is_union (C++11)
is_class (C++11)
is_function (C++11)
is_reference (C++11)

is_object (C++11)
is_scalar (C++11)
is_compound (C++11)
is_integral (C++11)
is_floating_point (C++11)
is_fundamental (C++11)
is_arithmetic (C++11)

is_lvalue_reference

(C++11)

is_rvalue_reference

(C++11)

is_member_pointer

(C++11)

is_member_object_pointer

(C++11)

is_member_function_pointer

(C++11)

Type properties

(C++11)

(C++11)

(C++11)

(C++11)

(C++14)

(C++11)

(C++17)

(C++23)

(C++11)(deprecated in C++26)

is_trivially_copyable

(C++11)

is_standard_layout

(C++11)

is_literal_type

(C++11)(until C++20*)

is_pod

(C++11)(deprecated in C++20)

(C++11)

(C++11)

(C++20)

(C++20)

(C++23)

has_unique_object_representations

(C++17)

Type trait constants

integral_constantbool_constanttrue_typefalse_type

(C++11)(C++17)(C++11)(C++11)

Metafunctions

conjunction

(C++17)

disjunction

(C++17)

negation

(C++17)

Supported operations

is_constructibleis_trivially_constructibleis_nothrow_constructible (C++11)(C++11)(C++11)
is_default_constructibleis_trivially_default_constructibleis_nothrow_default_constructible (C++11)(C++11)(C++11)
is_copy_constructibleis_trivially_copy_constructibleis_nothrow_copy_constructible (C++11)(C++11)(C++11)
is_move_constructibleis_trivially_move_constructibleis_nothrow_move_constructible (C++11)(C++11)(C++11)
is_assignableis_trivially_assignableis_nothrow_assignable (C++11)(C++11)(C++11)

is_copy_assignableis_trivially_copy_assignableis_nothrow_copy_assignable (C++11)(C++11)(C++11)
is_move_assignableis_trivially_move_assignableis_nothrow_move_assignable (C++11)(C++11)(C++11)
is_destructibleis_trivially_destructibleis_nothrow_destructible (C++11)(C++11)(C++11)
has_virtual_destructor (C++11)
is_swappable_withis_swappableis_nothrow_swappable_withis_nothrow_swappable (C++17)(C++17)(C++17)(C++17)

Relationships and property queries

is_same (C++11)
is_convertibleis_nothrow_convertible (C++11)(C++20)
is_layout_compatible (C++20)
is_pointer_interconvertible_base_of (C++20)
is_pointer_interconvertible_with_class (C++20)
is_corresponding_member (C++20)
reference_constructs_from_temporary (C++23)
reference_converts_from_temporary (C++23)

is_base_of (C++11)
is_virtual_base_of (C++26)
alignment_of (C++11)
rank (C++11)
extent (C++11)
is_invocableis_invocable_ris_nothrow_invocableis_nothrow_invocable_r (C++17)(C++17)(C++17)(C++17)

Type modifications

remove_cvremove_constremove_volatile (C++11)(C++11)(C++11)
add_cvadd_constadd_volatile (C++11)(C++11)(C++11)
make_signed (C++11)
make_unsigned (C++11)

remove_reference (C++11)
add_lvalue_referenceadd_rvalue_reference (C++11)(C++11)
remove_pointer (C++11)
add_pointer (C++11)
remove_extent (C++11)
remove_all_extents (C++11)

Type transformations

aligned_storage (C++11)(deprecated in C++23)
aligned_union (C++11)(deprecated in C++23)
decay (C++11)
remove_cvref (C++20)
result_ofinvoke_result (C++11)(until C++20*)(C++17)

conditional (C++11)
common_type (C++11)
common_reference (C++20)
underlying_type (C++11)
type_identity (C++20)
enable_if (C++11)
void_t (C++17)

Compile-time rational arithmetic

Compile-time integer sequences

integer_sequence

(C++14)

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

std::is_fundamental is aUnaryTypeTrait.

IfT is afundamental type (that is, arithmetic type,void, ornullptr_t), provides the member constantvalue equaltrue. For any other type,value isfalse.

If the program adds specializations forstd::is_fundamental orstd::is_fundamental_v, the behavior is undefined.

[edit]Template parameters

a type to check

[edit]Helper variable template

template<class T> constexprbool is_fundamental_v= is_fundamental<T>::value;		(since C++17)

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Inherited fromstd::integral_constant

Member constants

value

[static]

true ifT is a fundamental type,false otherwise
(public static member constant)

Member functions

operator bool	converts the object tobool, returnsvalue (public member function)
operator() (C++14)	returnsvalue (public member function)

Member types

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

[edit]Possible implementation

template<class T>struct is_fundamental:std::integral_constant<bool,std::is_arithmetic<T>::value||std::is_void<T>::value||std::is_same<std::nullptr_t,typenamestd::remove_cv<T>::type>::value// you can also use 'std::is_null_pointer<T>::value' instead in C++14>{};

[edit]Example

Run this code

#include <type_traits> static_assert(std::is_fundamental_v<int>==true);static_assert(std::is_fundamental_v<int&>==false);static_assert(std::is_fundamental_v<int*>==false);static_assert(std::is_fundamental_v<void>==true);static_assert(std::is_fundamental_v<void*>==false);static_assert(std::is_fundamental_v<float>==true);static_assert(std::is_fundamental_v<float&>==false);static_assert(std::is_fundamental_v<float*>==false);static_assert(std::is_fundamental_v<std::nullptr_t>==true);static_assert(std::is_fundamental_v<std::is_fundamental<int>>==false); class A{};static_assert(std::is_fundamental_v<A>==false);static_assert(std::is_fundamental_v<std::is_fundamental<A>::value_type>); int main(){}

[edit]See also

is_compound (C++11)	checks if a type is a compound type (class template)[edit]
is_arithmetic (C++11)	checks if a type is an arithmetic type (class template)[edit]
is_void (C++11)	checks if a type isvoid (class template)[edit]
is_null_pointer (C++11)(DR*)	checks if a type isstd::nullptr_t (class template)[edit]