Returns the next machine-representable number following x in the
    direction of y.

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

    Format

      #include  <math.h>

      double nextafter  (double x, double y);

      float nextafterf  (float x, float y);

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

  Additional Information (explode) :

• Arguments
• Description
• Return Values