std::isinf (3) - Linux Manuals

std::isinf: std::isinf

NAME

std::isinf - std::isinf

Synopsis

Defined in header <cmath>
bool isinf( float arg ); (1) (since C++11)
bool isinf( double arg ); (2) (since C++11)
bool isinf( long double arg ); (3) (since C++11)
bool isinf( IntegralType arg ); (4) (since C++11)

1-3) Determines if the given floating point number arg is a positive or negative infinity.
4) A set of overloads or a function template accepting the arg argument of any integral_type. Equivalent to (2) (the argument is cast to double).

Parameters

arg - floating point value

Return value

true if arg is infinite, false otherwise

Example

// Run this code

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

  int main()
  {
      std::cout << std::boolalpha
                << "isinf(NaN) = " << std::isinf(NAN) << '\n'
                << "isinf(Inf) = " << std::isinf(INFINITY) << '\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(0.0) = false
  isinf(exp(800)) = true
  isinf(DBL_MIN/2.0) = false