ROUND
Section: Linux Programmer's Manual (3)
Updated: 20010531
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NAME
round, roundf, roundl  round to nearest integer, away from zero
SYNOPSIS
#include <math.h>
double round(double x);
float roundf(float x);
long double roundl(long double x);
Compile with std=c99; link with lm.
DESCRIPTION
These functions round x to the nearest integer, but
round halfway cases away from zero (regardless of the current rounding
direction), instead of to the nearest even integer like
rint().
RETURN VALUE
The rounded integer value. If x is integral or infinite,
x itself is returned.
ERRORS
No errors other than EDOM and ERANGE can occur.
If x is NaN, then NaN is returned and
errno
may be set to EDOM.
NOTES
POSIX.12001 contains 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 errorhandling 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 IEEE754 standard 32bit and 64bit floating point numbers
the maximum value of the exponent is 128 (resp. 1024), and the number
of mantissa bits is 24 (resp. 53).)
CONFORMING TO
C99.
SEE ALSO
ceil(3),
floor(3),
lround(3),
nearbyint(3),
rint(3),
trunc(3)
Index
 NAME

 SYNOPSIS

 DESCRIPTION

 RETURN VALUE

 ERRORS

 NOTES

 CONFORMING TO

 SEE ALSO

linux.jgfs.net manual pages