relibc_openlibm/man/copysign.3

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.\"     from: @(#)ieee.3	6.4 (Berkeley) 5/6/91
.\" $FreeBSD: src/lib/msun/man/copysign.3,v 1.2 2007/01/09 01:02:05 imp Exp $
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.Dd January 26, 2005
.Dt COPYSIGN 3
.Os
.Sh NAME
.Nm copysign ,
.Nm copysignf ,
.Nm copysignl
.Nd copy sign
.Sh LIBRARY
.Lb libm
.Sh SYNOPSIS
.In math.h
.Ft double
.Fn copysign "double x" "double y"
.Ft float
.Fn copysignf "float x" "float y"
.Ft long double
.Fn copysignl "long double x" "long double y"
.Sh DESCRIPTION
The
.Fn copysign ,
.Fn copysignf
and
.Fn copysignl
functions
return
.Fa x
with its sign changed to
.Fa y Ns 's .
.Sh SEE ALSO
.Xr fabs 3 ,
.Xr fdim 3 ,
.Xr ieee 3 ,
.Xr math 3
.Sh STANDARDS
The
.Fn copysign ,
.Fn copysignf ,
and
.Fn copysignl
routines conform to
.St -isoC-99 .
They implement the Copysign function recommended by
.St -ieee754 .
.Sh HISTORY
The
.Fn copysign ,
.Fn copysignf ,
and
.Fn copysignl
functions appeared in
.Bx 4.3 ,
.Fx 2.0 ,
and
.Fx 5.3 ,
respectively.