std::is_fundamental - cppreference.com

From cppreference.com

template<classT>structis_fundamental;(since C++11)std::is_fundamental is a

UnaryTypeTrait

.

If T is a

fundamental type

(that is, arithmetic type, void,

std::nullptr_t

, std::meta::info(since C++26)), provides the member constant value equal true. For any other type, value is false.

If the program adds specializations for std::is_fundamental or std::is_fundamental_v, the behavior is undefined.

Template parameters

T - a type to check Helper variable template

template<classT>constexprboolis_fundamental_v=is_fundamental<T>::value;(since C++17)Inherited from

std::integral_constant

Member constants

value

[static]

true if T is a fundamental 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_typebooltypestd::integral_constant<bool,value>Possible implementation

template<classT>structis_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#if __cpp_impl_reflection > 0||std::is_reflection_v<T>#endif>{};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);classA{};static_assert(std::is_fundamental_v<A>==false);static_assert(std::is_fundamental_v<std::is_fundamental<A>::value_type>);intmain(){}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 is void
(class template)

[edit]

is_null_pointer

(C++11)(DR*)

checks if a type is

std::nullptr_t

(class template)

[edit]

is_reflection

(C++26)

checks if a type is std::meta::info
(class template)

[edit]

is_fundamental_type

(C++26)

checks if reflection represents a fundamental type
(function)

[edit]