Manpage of COPYSIGN

COPYSIGN

Section: Linux Programmer's Manual (3)
Updated: 2016-03-15
Index
 

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 xand whose sign is taken from y.

If xis a NaN, a NaN with the sign bit of yis returned.  

ERRORS

No errors occur.  

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).
InterfaceAttributeValue
copysign(), copysignf(), copysignl() Thread safetyMT-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.  

SEE ALSO

signbit(3)


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
ATTRIBUTES
CONFORMING TO
NOTES
SEE ALSO

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Time: 22:27:51 GMT, June 20, 2016