Originální popis anglicky:
nearbyint, nearbyintf, nearbyintl, rint, rintf, rintl - round to nearest integer
Návod, kniha: Linux Programmer's Manual
#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.
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.
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 EDOM.
SUSv2 and POSIX 1003.1-2001 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).)
The
rint() function conforms to BSD 4.3. The other functions are from
C99.
ceil(3),
floor(3),
lrint(3),
nearbyint(3),
round(3),
trunc(3)
