Name
copysign, copysignf, copysignl — copy sign of a number
Synopsis
#include <math.h>
double
copysign( |
double x, |
double y); |
float
copysignf( |
float x, |
float y); |
long double
copysignl( |
long double x, |
long double y); |
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DESCRIPTION
These functions return a value whose absolute value
matches that of x,
but whose sign bit matches that of y.
For example, copysign(42.0, −1.0) and copysign(−42.0, −1.0) both return −42.0.
RETURN VALUE
On success, these functions return a value whose magnitude
is taken from x and
whose sign is taken from y.
If x is a NaN, a
NaN with the sign bit of y is returned.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
copysign(), copysignf(), copysignl() |
Thread safety | MT-Safe |
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008. This function is defined in IEC 559 (and the appendix with recommended functions in IEEE 754/IEEE 854).
NOTES
On architectures where the floating-point formats are not IEEE 754 compliant, these functions may treat a negative zero as positive.
COLOPHON
This page is part of release 4.07 of the Linux man-pages project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
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Copyright 1993 David Metcalfe (davidprism.demon.co.uk) %%%LICENSE_START(VERBATIM) 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 Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date.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. %%%LICENSE_END 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 by Walter Harms (walter.harmsinformatik.uni-oldenburg.de) |