Rounds its argument to an integral value according to the current
    IEEE rounding direction specified by the user.

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

    Format

      #include  <math.h>

      double rint  (double x);

      float rintf  (float x,);

      long double rintl  (long double x);

  Additional Information (explode) :

• Argument
• Description
• Return Values