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