std::numeric_limits::has_infinity(3)

NAME
std::numeric_limits::has_infinity - std::numeric_limits::has_infinity

Synopsis
   static const bool has_infinity; (until C++11)
   static constexpr bool has_infinity; (since C++11)
   The value of std::numeric_limits<T>::has_infinity is true for all types T capable of
   representing the positive infinity as a distinct special value. This constant is
   meaningful for all floating-point types and is guaranteed to be true if
   std::numeric_limits<T>::is_iec559 == true.

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

Example
// Run this code
 #include <iostream>
 #include <limits>
 int main()
 {
     std::cout << std::boolalpha
               << std::numeric_limits<int>::has_infinity << '\n'
               << std::numeric_limits<long>::has_infinity << '\n'
               << std::numeric_limits<float>::has_infinity << '\n'
               << std::numeric_limits<double>::has_infinity << '\n';
 }

Possible output:
 false
 false
 true
 true

See also
   infinity returns the positive infinity value of the given floating-point
   [static] type
                     (public static member function)
   has_quiet_NaN identifies floating-point types that can represent the special
   [static] value "quiet not-a-number" (NaN)
                     (public static member constant)
   has_signaling_NaN identifies floating-point types that can represent the special
   [static] value "signaling not-a-number" (NaN)
                     (public static member constant)