**round**

SYNOPSIS
#include <math.h>
double round(double x);
float roundf(float x);
long double roundl(long double x);
Link with -lm.
Feature Test Macro Requirements for glibc (see **feature_test_macros(7)**):
round(), roundf(), roundl():
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or cc -std=c99
DESCRIPTION
These functions round x to the nearest integer, but round halfway cases
away from zero (regardless of the current rounding direction, see
**fenv(3)**), instead of to the nearest even integer like **rint(3)**.
For example, round(0.5) is 1.0, and round(-0.5) is -1.0.
RETURN VALUE
These functions return the rounded integer value.
If x is integral, +0, -0, NaN, or infinite, x itself is returned.
ERRORS
No errors occur. POSIX.1-2001 documents a range error for overflows,
but see NOTES.
VERSIONS
These functions first appeared in glibc in version 2.1.
CONFORMING TO
C99, POSIX.1-2001.
NOTES
POSIX.1-2001 contains text about overflow (which might set errno to
ERANGE, or raise an FE_OVERFLOW 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 max-
imum 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 (respectively, 1024), and the num-
ber of mantissa bits is 24 (respectively, 53).)
If you want to store the rounded value in an integer type, you probably
want to use one of the functions described in **lround(3)** instead.
SEE ALSO
**ceil(3)**, **floor(3)**, **lround(3)**, **nearbyint(3)**, **rint(3)**, **trunc(3)**

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