Name
drem, dremf, dreml, remainder, remainderf, remainderl — floating-point remainder function
Synopsis
#include <math.h> /* The C99 versions */
double
remainder( |
double x, |
double y); |
float
remainderf( |
float x, |
float y); |
long double
remainderl( |
long double x, |
long double y); |
/* Obsolete synonyms */
double
drem( |
double x, |
double y); |
float
dremf( |
float x, |
float y); |
long double
dreml( |
long double x, |
long double y); |
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DESCRIPTION
The remainder() function
computes the remainder of dividing x by y. The return value is
x−n*y,
where n is the value
x / y, rounded to the
nearest integer. If the absolute value of x−n*y
is 0.5, n is chosen to be
even.
These functions are unaffected by the current rounding mode (see fenv(3)).
The drem() function does
precisely the same thing.
RETURN VALUE
On success, these functions return the floating-point
remainder, x−n*y.
If the return value is 0, it has the sign of x.
If x or y is a NaN, a NaN is
returned.
If x is an
infinity, and y is
not a NaN, a domain error occurs, and a NaN is returned.
If y is zero, and
x is not a NaN, a
domain error occurs, and a NaN is returned.
ERRORS
See math_error(7) for information on how to determine whether an error has occurred when calling these functions.
The following errors can occur:
- Domain error:
xis an infinity andyis not a NaN -
An invalid floating-point exception (
FE_INVALID) is raised.These functions do not set
errnofor this case. - Domain error:
yis zero -
errnois set to EDOM. An invalid floating-point exception (FE_INVALID) is raised.
CONFORMING TO
The functions remainder(),
remainderf(), and remainderl() are specified in C99 and
POSIX.1-2001.
The function drem() is from
4.3BSD. The float and long double variants dremf() and dreml() exist on some systems, such as
Tru64 and glibc2. Avoid the use of these functions in favor
of remainder() etc.
BUGS
The call
remainder(nan(""), 0);
returns a NaN, as expected, but wrongly causes a domain error; it should yield a silent NaN.
COLOPHON
This page is part of release 3.33 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at http://man7.org/linux/man-pages/.
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Copyright 1993 David Metcalfe (davidprism.demon.co.uk) and Copyright 2008, Linux Foundation, written by Michael Kerrisk <mtk.manpagesgmail.com> Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. References consulted: Linux libc source code Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) 386BSD man pages Modified 1993-07-24 by Rik Faith (faithcs.unc.edu) Modified 2002-08-10 Walter Harms (walter.harmsinformatik.uni-oldenburg.de) Modified 2003-11-18, 2004-10-05 aeb |