Defined in header <type_traits> | ||
|---|---|---|
template< class T > struct is_integral; | (since C++11) |
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, 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.
| T | - | a type to check |
template< class T > inline constexpr bool is_integral_v = is_integral<T>::value; | (since C++17) |
| value
[static] | true if T is an integral type , false otherwise (public static member constant) |
| operator bool | converts the object to bool, returns value (public member function) |
| operator()
(C++14) | returns value (public member function) |
| Type | Definition |
|---|---|
value_type | bool |
type | std::integral_constant<bool, value> |
#include <iostream>
#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;
}
int main()
{
std::cout << std::boolalpha;
std::cout << std::is_integral<A>::value << '\n';
std::cout << std::is_integral<E>::value << '\n';
std::cout << std::is_integral<float>::value << '\n';
std::cout << std::is_integral<int>::value << '\n';
std::cout << std::is_integral<bool>::value << '\n';
std::cout << f(123) << '\n';
}Output:
false false false true true 123
|
[static] | identifies integer types (public static member constant of std::numeric_limits<T>) |
|
(C++11) | checks if a type is a floating-point type (class template) |
|
(C++11) | checks if a type is an arithmetic type (class template) |
|
(C++11) | checks if a type is an enumeration type (class template) |
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