HP-UX Reference (11i v1 00/12) - 3 Library Functions N-Z (vol 7)

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STANDARD Printed by: Nora Chuang [nchuang] STANDARD
/build/1111/BRICK/man3/nan.3m
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r
rint(3M) rint(3M)
NAME
rint(), nearbyint() - round to nearest int function
SYNOPSIS
#include <math.h>
double rint(double x);
double nearbyint(double x);
DESCRIPTION
rint() and nearbyint() return the integer (represented as a double precision number) nearest x
according to the current rounding direction mode. These functions meet the requirement of the IEEE-754
standard for an operation that rounds to integer in floating-point format.
The two functions are identical except that rint() raises the inexact exception, while nearbyint()
does not.
In the default rounding direction (round to nearest), rint(x) is the integer nearest x with the additional
stipulation that if |rint(x) − x|=1/2, then
rint(x) is even. (The same statement applies to
nearbyint(x).)
If the current rounding direction is toward negative infinity, rint() and nearbyint() are identical to
floor(). If the current rounding direction is toward positive infinity, rint() and nearbyint() are
identical to
ceil().
The ISO/ANSI C committee has approved the rint() and nearbyint()
functions for inclusion in the
C9X draft standard.
To use these functions, compile either with the default
-Ae option or with the -Aa
and
-D_HPUX_SOURCE options. Make sure your program includes <
math.h>. Link in the math library by
specifying
-lm on the compiler or linker command line.
RETURN VALUE
If x is ±INFINITY, the rint() and nearbyint() functions return ±INFINITY respectively.
If x is NaN, the
rint() and nearbyint() functions return NaN.
ERRORS
No errors are defined.
SEE ALSO
ceil(3M), floor(3M), fabs(3M), fmod(3M), fegetround(3M), fesetround(3M), lrint(3M), llrint(3M), lround(3M),
llround(3M), round(3M), trunc(3M), math(5), fenv(5).
STANDARDS CONFORMANCE
rint(): XPG4.2, IEEE-754
HP-UX Release 11i: December 2000 − 1 − Section 3−−775
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