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std::numeric_limits<T>::is_integer

static const bool is_integer;
 (until C++11) 
static constexpr bool is_integer;
 (since C++11)

The value of std::numeric_limits<T>::is_integer is true for all integer arithmetic types T and false otherwise. This constant is meaningful for all specializations.

Standard specializations

T value of std::numeric_limits<T>::is_integer
/* non-specialized */ false
bool true
char true
signed char true
unsigned char true
wchar_t true
char8_t (since C++20) true
char16_t (since C++11) true
char32_t (since C++11) true
short true
unsigned short true
int true
unsigned int true
long true
unsigned long true
long long (since C++11) true
unsigned long long (since C++11) true
float false
double false
long double false

Example

#include <cstddef>
#include <cstdint>
#include <limits>
 
static_assert
(
        std::numeric_limits<bool>::is_integer
    &&  std::numeric_limits<std::size_t>::is_integer
    &&  std::numeric_limits<std::int32_t>::is_integer
    &&  std::numeric_limits<std::int64_t>::is_integer
    &&  std::numeric_limits<decltype(42)>::is_integer
    && !std::numeric_limits<int*>::is_integer
    && !std::numeric_limits<float>::is_integer
    && !std::numeric_limits<double>::is_integer
    && !std::numeric_limits<long double>::is_integer
    && !std::numeric_limits<decltype([](){})>::is_integer // P0315R4
);
 
int main() {}

See also

(C++11)
 checks if a type is an integral type
(class template)
[static]
 identifies signed types
(public static member constant)
[static]
 identifies exact types
(public static member constant)
[static]
 identifies types that represent a finite set of values
(public static member constant)

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https://en.cppreference.com/w/cpp/types/numeric_limits/is_integer