is_nan

Determines if the double is not-a-number (NaN).

Example: Check whether the double represents a number:

public static int main (string[] args) {
	double d1 = -1.1;
	double d2 = 1.1;
	double d3 = double.NAN;
	double d4 = Math.sin (double.INFINITY); // domain error

	// Output: ``false``
	print ("%s\n", d1.is_nan ().to_string ());
	// Output: ``false``
	print ("%s\n", d2.is_nan ().to_string ());
	// Output: ``true``
	print ("%s\n", d3.is_nan ().to_string ());
	// Output: ``true``
	print ("%s\n", d4.is_nan ().to_string ());

	return 0;
}

valac --pkg glib-2.0 double.is_nan.vala -X -lm