Returns the value 1 (TRUE) if either or both of the arguments is
    a NaN. Otherwise, it returns the value 0 (FALSE).

    This function is supported on OpenVMS Integrity servers and
    Alpha only.

    Format

      #include  <math.h>

      double unordered  (double x, double y);

      float unorderedf  (float x, float y);

      long double unorderedl  (long double x, long double y);

1 - Arguments

 x

    A real number.

 y

    A real number.

2 - Return Values

    1                  Either or both of the arguments is a NaN.
    0                  Neither argument is a NaN.