COPYSIGN
Section: Linux Programmer's Manual (3)
Updated: 20170915
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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():

_ISOC99_SOURCE  _POSIX_C_SOURCE >= 200112L
 /* Since glibc 2.19: */ _DEFAULT_SOURCE
 /* Glibc versions <= 2.19: */ _BSD_SOURCE  _SVID_SOURCE
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.
ERRORS
No errors occur.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
Interface  Attribute  Value

copysign(),
copysignf(),
copysignl()
 Thread safety  MTSafe

CONFORMING TO
C99, POSIX.12001, POSIX.12008.
This function is defined in IEC 559 (and the appendix with
recommended functions in IEEE 754/IEEE 854).
NOTES
On architectures where the floatingpoint formats are not IEEE 754 compliant,
these
functions may treat a negative zero as positive.
SEE ALSO
signbit(3)
COLOPHON
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Index
 NAME

 SYNOPSIS

 DESCRIPTION

 RETURN VALUE

 ERRORS

 ATTRIBUTES

 CONFORMING TO

 NOTES

 SEE ALSO

 COLOPHON

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