# copysign(3) [netbsd man page]

COPYSIGN(3) BSD Library Functions Manual COPYSIGN(3)NAME

copysign, copysignf, copysignlfunctions to manipulate signs--LIBRARY

Math Library (libm, -lm)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);DESCRIPTION

The copysign(), copysignf(), and copysignl() functions return a value whose absolute value matches x, but whose sign bit is taken from y.RETURN VALUES

Upon successful completion, all three functions return a value with the magnitude of x and the sign of y. If x is NaN , the functions return a NaN with the sign of y.SEE ALSO

math(3), signbit(3)STANDARDS

The described functions conform to ISO/IEC 9899:1999 (``ISO C99'').CAVEATS

Note that on implementations that represent a signed zero but do not treat negative zero consistently in arithmetic operations, these func- tions may regard the sign of zero as positive.BSD

April 13, 2011 BSD

## Check Out this Related Man Page

COPYSIGN(3) Linux Programmer's Manual COPYSIGN(3)NAME

copysign, copysignf, copysignl - copy sign of a numberSYNOPSIS

#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 withFeature 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-lm.-std=c99DESCRIPTION

The copysign() 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.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 posi- tive.SEE ALSO

signbit(3)COLOPHON

This page is part of release 3.53 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/.GNU

2012-03-25 COPYSIGN(3)