rint

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

#include <math.h>
 I double nearbyint(double  x );

I float nearbyintf(float  x );

I long double nearbyintl(long double  x );
 I double rint(double  x );

I float rintf(float  x );

I long double rintl(long double  x );

Link with -lm.

The R 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 R rint () functions do the same, but will raise the inexact exception when the result differs in value from the argument.

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

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

C99.

SUSv2 and POSIX.1-2001 contain text about overflow (which might set errno to R 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).)

ceil(3), floor(3), lrint(3), nearbyint(3), round(3), trunc(3)