RINT(3) Linux Programmers Manual RINT(3)
NAME
nearbyint, nearbyintf, nearbyintl, rint, rintf, rintl  round to near
est integer
SYNOPSIS
#include
double nearbyint(double x);
float nearbyintf(float x);
long double nearbyintl(long double x);
double rint(double x);
float rintf(float x);
long double rintl(long double x);
Link with lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
nearbyint(), nearbyintf(), nearbyintl(): _XOPEN_SOURCE >= 600 
_ISOC99_SOURCE; or cc std=c99
rint(), rintf(), rintl(): _BSD_SOURCE  _SVID_SOURCE 
_XOPEN_SOURCE >= 500  _ISOC99_SOURCE; or cc std=c99
DESCRIPTION
The nearbyint() functions round their argument to an integer value in
floating point format, using the current rounding direction and without
raising the inexact exception.
The rint() functions do the same, but will raise the inexact exception
when the result differs in value from the argument.
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.
CONFORMING TO
C99.
NOTES
SUSv2 and POSIX.12001 contain text about overflow (which might set
errno to ERANGE, or raise an exception). In practice, the result can
not overflow on any current machine, so this errorhandling stuff is
just nonsense. (More precisely, overflow can happen only when the max
imum value of the exponent is smaller than the number of mantissa bits.
For the IEEE754 standard 32bit and 64bit floating point numbers the
maximum value of the exponent is 128 (respectively, 1024), and the num
ber of mantissa bits is 24 (respectively, 53).)
SEE ALSO
ceil(3), floor(3), lrint(3), round(3), trunc(3)
COLOPHON
This page is part of release 3.05 of the Linux manpages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/manpages/.
20070726 RINT(3)
