roundl

ROUND(3)                   Linux Programmer's Manual                  ROUND(3)



NAME
       round, roundf, roundl - round to nearest integer, away from zero

SYNOPSIS
       #include <math.h>

       double round(double x);
       float roundf(float x);
       long double roundl(long double x);

DESCRIPTION
       These functions round x to the nearest integer, but round halfway cases
       away from zero (regardless of the current rounding direction),  instead
       of to the nearest even integer like rint().

RETURN VALUE
       The  rounded  integer  value. If x is integral or infinite, x itself is
       returned.

ERRORS
       No errors other than EDOM and ERANGE can occur.  If x is NaN, then  NaN
       is returned and errno may be set to EDOM.

NOTES
       POSIX  1003.1-2001  contains text about overflow (which might set errno
       to ERANGE, or raise an exception).   In  practice,  the  result  cannot
       overflow  on  any current machine, so this error-handling stuff is just
       nonsense.  (More precisely, overflow can happen only when  the  maximum
       value of the exponent is smaller than the number of mantissa bits.  For
       the IEEE-754 standard 32-bit and 64-bit floating point numbers the max-
       imum  value of the exponent is 128 (resp. 1024), and the number of man-
       tissa bits is 24 (resp. 53).)

CONFORMING TO
       C99.

SEE ALSO
       ceil(3), floor(3), lround(3), nearbyint(3), rint(3), trunc(3)



                                  2001-05-31                          ROUND(3)