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    std::is_fundamental

    From cppreference.com
     
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    Defined in header <type_traits> 
    template< class T >
struct is_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< class T >
constexpr bool is_fundamental_v = is_fundamental<T>::value;
    		(since C++17)
    [edit]

    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_type bool
    type std::integral_constant<bool, value>

    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, typename std::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);

class A {};
static_assert(std::is_fundamental_v<A> == false);
static_assert(std::is_fundamental_v<std::is_fundamental<A>::value_type>);

int main() {}

    See also

    (C++11)
    		 checks if a type is a compound type
    (class template) [edit]
    (C++11)
    		 checks if a type is an arithmetic type
    (class template) [edit]
    (C++11)
    		 checks if a type is void
    (class template) [edit]
    (C++11)(DR*)
    		 checks if a type is std::nullptr_t
    (class template) [edit]
    (C++26)
    		 checks if a type is std::meta::info
    (class template) [edit]