redhat man page for roundf

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
       maximum value of the exponent is 128 (resp. 1024), and the number of mantissa 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)