Equivalent to the nextafter function, with exceptions noted in
    the Description.

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

    Format

      #include  <math.h>

      double nexttoward  (double x, long double y);

      float nexttowardf  (float x, long double y);

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

  Additional Information (explode) :

• Arguments
• Description
• Return Values