4.3BSD - /usr/man/cat3/fabs.0

FLOOR(3M)                                                            FLOOR(3M)


NAME
       fabs, floor, ceil, rint - absolute value, floor, ceiling, and round-to-
       nearest functions

SYNOPSIS
       #include <math.h>

       double floor(x)
       double x;

       double ceil(x)
       double x;

       double fabs(x)
       double x;

       double rint(x)
       double x;

DESCRIPTION
       Fabs returns the absolute value |x|.

       Floor returns the largest integer no greater than x.

       Ceil returns the smallest integer no less than x.

       Rint returns the integer (represented as  a  double  precision  number)
       nearest x in the direction of the prevailing rounding mode.

NOTES
       On  a  VAX,  rint(x)  is equivalent to adding half to the magnitude and
       then rounding towards zero.

       In the default rounding mode, to nearest, on a machine that conforms to
       IEEE 754, rint(x) is the integer nearest x with the additional stipula‐
       tion that if |rint(x)-x|=1/2 then  rint(x)  is  even.   Other  rounding
       modes  can  make  rint  act  like floor, or like ceil, or round towards
       zero.

       Another way to obtain an integer near x is to declare (in C)
              double x;     int k;    k = x;
       Most C compilers round x towards 0 to get the integer k,  but  some  do
       otherwise.   If in doubt, use floor, ceil, or rint first, whichever you
       intend.  Also note that, if x is larger than  k  can  accommodate,  the
       value  of k and the presence or absence of an integer overflow are hard
       to predict.

SEE ALSO
       abs(3), ieee(3M), math(3M)


4th Berkeley Distribution        May 12, 1986                        FLOOR(3M)