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std::isinf(3)		       C++ Standard Libary		   std::isinf(3)

NAME
     std::isinf - std::isinf

Synopsis
	Defined in header <cmath>
	bool isinf( float num );
								     (since
     C++11)
	bool  isinf(  double  num  );					  (until
     C++23)

	bool isinf( long double num );
	constexpr bool isinf( /*  floating-point-type  */  num	 (1)	  (since
     C++23)
	);
	Additional overloads
	Defined in header <cmath>
	template<  class  Integer  >				     (A)  (since
     C++11)
	bool isinf( Integer num );				      (constexpr
     since C++23)

	1)  Determines	if  the given floating-point number num is a positive or
     negative
	infinity.
	The library provides overloads	for  all  cv-unqualified  floating-point
     types as the
	type of the parameter num.
	(since C++23)
	A)  Additional	overloads  are provided for all integer types, which are
     treated as
	double.

Parameters
	num - floating-point or integer value

Return value
	true if num is infinite, false otherwise.

Notes
	GCC and Clang support a -ffinite-math option  (additionally  implied  by
     -ffast-math),
	which  allows the respective compiler to assume the nonexistence of spe-
     cial IEEE-754
	floating point values such as NaN, infinity, or negative zero. In  other
     words,
	std::isinf is assumed to always return false under this option.

	The additional overloads are not required to be provided exactly as (A).
     They only
	need  to  be sufficient to ensure that for their argument num of integer
     type,
	std::isinf(num)  has  the  same  effect  as  std::isinf(static_cast<dou-
     ble>(num)).

Example
     // Run this code

      #include <cfloat>
      #include <cmath>
      #include <iostream>
      #include <limits>

      int main()
      {
	  const double max = std::numeric_limits<double>::max();
	  const double inf = std::numeric_limits<double>::infinity();

	  std::cout << std::boolalpha
		    << "isinf(NaN) = " << std::isinf(NAN) << '\n'
		    << "isinf(Inf) = " << std::isinf(INFINITY) << '\n'
		    << "isinf(max) = " << std::isinf(max) << '\n'
		    << "isinf(inf) = " << std::isinf(inf) << '\n'
		    << "isinf(0.0) = " << std::isinf(0.0) << '\n'
		    << "isinf(exp(800)) = " << std::isinf(std::exp(800)) << '\n'
		    <<	"isinf(DBL_MIN/2.0)  = " << std::isinf(DBL_MIN / 2.0) <<
     '\n';
      }

Output:
      isinf(NaN) = false
      isinf(Inf) = true
      isinf(max) = false
      isinf(inf) = true
      isinf(0.0) = false
      isinf(exp(800)) = true
      isinf(DBL_MIN/2.0) = false

See also
	fpclassify categorizes the given floating-point value
	(C++11)    (function)
	isfinite   checks if the given number has finite value
	(C++11)    (function)
	isnan	   checks if the given number is NaN
	(C++11)    (function)
	isnormal   checks if the given number is normal
	(C++11)    (function)
	C documentation for
	isinf

http://cppreference.com 	   2024.06.10			   std::isinf(3)
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