COPYSIGN
COPYSIGN
Section: Linux Programmer's Manual (3) Updated: 2010-09-20 Local index
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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 );
Link with -lm .

Feature Test Macro Requirements for glibc (see
feature_test_macros (7)):

copysign (),
copysignf (),
copysignl ():

_SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or
cc -std=c99
DESCRIPTION
The
copysign ()
functions return a value whose absolute value matches
that of x , but whose sign bit matches that of y .
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.

ERRORS
No errors occur.
CONFORMING TO
C99, POSIX.1-2001.
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,
the
copysign ()
functions may treat a negative zero as positive.
SEE ALSO
signbit (3)
COLOPHON
This page is part of release 3.27 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.

Index
NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
CONFORMING TO
NOTES
SEE ALSO
COLOPHON
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Time: 21:43:46 GMT, April 16, 2011