unordered

   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);
 

Additional information available:

Arguments       Return_Values