RINT(3) Library Functions Manual RINT(3)

nearbyint, nearbyintf, nearbyintl, rint, rintf, rintl
round to integral value in floating-point format

Math Library (libm, -lm)

#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);

The rint(), rintf(), and rintl() functions return the integral value nearest to x according to the prevailing rounding mode. These functions raise an inexact exception when the original argument is not an exact integer.

The nearbyint(), nearbyintf(), and nearbyintl() functions perform the same operation, except that they do not raise an inexact exception.

abs(3), ceil(3), fabs(3), fenv(3), floor(3), lrint(3), math(3), round(3)

A rint() function appeared in Version 6 AT&T UNIX.
September 13, 2015 NetBSD 9.2