Defined in header <cmath>
#define INFINITY /*implementation defined*/
(since C++11)

If the implementation supports floating-point infinities, the macro INFINITY expands to constant expression of type float which evaluates to positive or unsigned infinity.

If the implementation does not support floating-point infinities, the macro INFINITY expands to a positive value that is guaranteed to overflow a float at compile time, and the use of this macro generates a compiler warning.

See also

checks if the given number is infinite
indicates the overflow value for float, double and long double respectively
(macro constant)
identifies floating-point types that can represent the special value "positive infinity"
(public static member constant of std::numeric_limits<T>)
returns the positive infinity value of the given floating-point type
(public static member function of std::numeric_limits<T>)

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