RINT

Section: Linux Programmer's Manual (3)
Updated: 2001-05-31
Index Return to Main Contents
 

NAME

nearbyint, nearbyintf, nearbyintl, rint, rintf, rintl - round to nearest integer  

SYNOPSIS

#include <math.h>

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.  

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.  

NOTES

SUSv2 and POSIX.1-2001 contain 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), lrint(3), nearbyint(3), round(3), trunc(3)


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
NOTES
CONFORMING TO
SEE ALSO

linux.jgfs.net manual pages