1.\" $NetBSD: copysign.3,v 1.1 2011/04/13 04:57:10 jruoho Exp $ 2.\" 3.\" Copyright (c) 2011 Jukka Ruohonen <jruohonen@iki.fi> 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 16.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 17.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 18.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 19.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 20.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 21.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 22.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 23.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 24.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 25.\" POSSIBILITY OF SUCH DAMAGE. 26.\" 27.Dd April 13, 2011 28.Dt COPYSIGN 3 29.Os 30.Sh NAME 31.Nm copysign , 32.Nm copysignf , 33.Nm copysignl 34.Nd functions to manipulate signs 35.Sh LIBRARY 36.Lb libm 37.Sh SYNOPSIS 38.In math.h 39.Ft double 40.Fn copysign "double x" "double y" 41.Ft float 42.Fn copysignf "float x" "float y" 43.Ft long double 44.Fn copysignl "long double x" "long double y" 45.Sh DESCRIPTION 46The 47.Fn copysign , 48.Fn copysignf , 49and 50.Fn copysignl 51functions return a value whose absolute value matches 52.Fa x , 53but whose sign bit is taken from 54.Fa y . 55.Sh RETURN VALUES 56Upon successful completion, 57all three functions return a value with the magnitude of 58.Fa x 59and the sign of 60.Fa y . 61If 62.Fa x 63is 64\*(Na , 65the functions return a 66\*(Na 67with the sign of 68.Fa y . 69.Sh SEE ALSO 70.Xr math 3 , 71.Xr signbit 3 72.Sh STANDARDS 73The described functions conform to 74.St -isoC-99 . 75.\" 76.\" XXX: Verify this. 77.\" 78.\" The functions are also recommended by 79.\" .St -ieee754 80.\" 81.\" .Sh HISTORY 82.\" 83.\" XXX: Fill this. 84.\" 85.\" These functions first appeared in ???. 86.\" 87.Sh CAVEATS 88Note that on implementations that represent a signed zero 89but do not treat negative zero consistently in arithmetic operations, 90these functions may regard the sign of zero as positive. 91