1.\" Copyright (c) 1985, 1991 Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" from: @(#)ieee.3 6.4 (Berkeley) 5/6/91 29.\" $FreeBSD$ 30.\" 31.Dd January 26, 2005 32.Dt COPYSIGN 3 33.Os 34.Sh NAME 35.Nm copysign , 36.Nm copysignf , 37.Nm copysignl 38.Nd copy sign 39.Sh LIBRARY 40.Lb libm 41.Sh SYNOPSIS 42.In math.h 43.Ft double 44.Fn copysign "double x" "double y" 45.Ft float 46.Fn copysignf "float x" "float y" 47.Ft long double 48.Fn copysignl "long double x" "long double y" 49.Sh DESCRIPTION 50The 51.Fn copysign , 52.Fn copysignf 53and 54.Fn copysignl 55functions 56return 57.Fa x 58with its sign changed to 59.Fa y Ns 's . 60.Sh SEE ALSO 61.Xr fabs 3 , 62.Xr fdim 3 , 63.Xr ieee 3 , 64.Xr math 3 65.Sh STANDARDS 66The 67.Fn copysign , 68.Fn copysignf , 69and 70.Fn copysignl 71routines conform to 72.St -isoC-99 . 73They implement the Copysign function recommended by 74.St -ieee754 . 75.Sh HISTORY 76The 77.Fn copysign , 78.Fn copysignf , 79and 80.Fn copysignl 81functions appeared in 82.Bx 4.3 , 83.Fx 2.0 , 84and 85.Fx 5.3 , 86respectively. 87