NAME¶

std::is_integral - std::is_integral

Synopsis¶

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

Checks whether T is an integral type. Provides the member constant value which is
equal to true, if T is the type bool, char
, char8_t
(since C++20), char16_t, char32_t, wchar_t, short, int, long, long long, or any
implementation-defined extended integer types, including any signed, unsigned, and
cv-qualified variants. Otherwise, value is equal to false.

The behavior of a program that adds specializations for is_integral
or is_integral_v
(since C++17) is undefined.

Template parameters¶

T - a type to check

Helper variable template

template< class T > (since C++17)
inline constexpr bool is_integral_v = is_integral<T>::value;

Inherited from std::integral_constant

Member constants¶

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

Member functions¶

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

Member types¶

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

Example¶

// Run this code

#include <iostream>
#include <iomanip>
#include <type_traits>

class A {};

enum E : int {};

template <class T>
T f(T i)
{
static_assert(std::is_integral<T>::value, "Integral required.");
return i;
}

#define SHOW(...) std::cout << std::setw(29) << #__VA_ARGS__ << " == " << __VA_ARGS__ << '\n'

int main()
{
std::cout << std::boolalpha;

SHOW( std::is_integral<A>::value );
SHOW( std::is_integral_v<E> );
SHOW( std::is_integral_v<float> );
SHOW( std::is_integral_v<int> );
SHOW( std::is_integral_v<const int> );
SHOW( std::is_integral_v<bool> );
SHOW( f(123) );
}

Output:¶

std::is_integral<A>::value == false
std::is_integral_v<E> == false
std::is_integral_v<float> == false
std::is_integral_v<int> == true
std::is_integral_v<const int> == true
std::is_integral_v<bool> == true
f(123) == 123

See also¶

integral specifies that a type is an integral type
(C++20) (concept)
is_integer identifies integer types
[static] (public static member constant of std::numeric_limits<T>)
is_floating_point checks if a type is a floating-point type
(C++11) (class template)
is_arithmetic checks if a type is an arithmetic type
(C++11) (class template)
is_enum checks if a type is an enumeration type
(C++11) (class template)