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. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" from: @(#)ieee.3 6.4 (Berkeley) 5/6/91 33.\" $FreeBSD$ 34.\" 35.Dd February 25, 1994 36.Dt IEEE 3 37.Os 38.Sh NAME 39.Nm copysign , 40.Nm copysignf , 41.Nm copysignl , 42.Nm finite , 43.Nm finitef , 44.Nm ilogb , 45.Nm ilogbf , 46.Nm nextafter , 47.Nm nextafterf , 48.Nm remainder , 49.Nm remainderf , 50.Nm scalbn , 51.Nm scalbnf 52.Nd functions for IEEE arithmetic 53.Sh LIBRARY 54.Lb libm 55.Sh SYNOPSIS 56.In math.h 57.Ft double 58.Fn copysign "double x" "double y" 59.Ft float 60.Fn copysignf "float x" "float y" 61.Ft long double 62.Fn copysignl "long double x" "long double y" 63.Ft int 64.Fn finite "double x" 65.Ft int 66.Fn finitef "float x" 67.Ft int 68.Fn ilogb "double x" 69.Ft int 70.Fn ilogbf "float x" 71.Ft double 72.Fn nextafter "double x" "double y" 73.Ft float 74.Fn nextafterf "float x" "float y" 75.Ft double 76.Fn remainder "double x" "double y" 77.Ft float 78.Fn remainderf "float x" "float y" 79.Ft double 80.Fn scalbn "double x" "int n" 81.Ft float 82.Fn scalbnf "float x" "int n" 83.Sh DESCRIPTION 84These functions are required or recommended by 85.St -ieee754 . 86.Pp 87.Fn copysign , 88.Fn copysignf 89and 90.Fn copysignl 91return 92.Fa x 93with its sign changed to 94.Fa y Ns 's . 95.Pp 96.Fn finite 97and 98.Fn finitef 99return the value 1 just when 100\-\*(If \*(Lt 101.Fa x 102\*(Lt +\*(If; 103otherwise a 104zero is returned 105(when 106.Pf \\*(Ba Ns Fa x Ns \\*(Ba 107= \*(If or 108.Fa x 109is \*(Na). 110.Pp 111.Fn ilogb 112and 113.Fn ilogbf 114return 115.Fa x Ns 's exponent, 116in integer format. 117.Fn ilogb \*(Pm\*(If 118returns 119.Dv INT_MAX 120and 121.Fn ilogb 0 122returns 123.Dv INT_MIN . 124.Pp 125.Fn nextafter 126and 127.Fn nextafterf 128return the next machine representable number from 129.Fa x 130in direction 131.Fa y . 132.Pp 133.Fn remainder 134and 135.Fn remainderf 136return the remainder 137.Fa r 138:= 139.Fa x 140\- 141.Fa n\(**y 142where 143.Fa n 144is the integer nearest the exact value of 145.Bk -words 146.Fa x Ns / Ns Fa y ; 147.Ek 148moreover if 149.Pf \\*(Ba Fa n 150\- 151.Sm off 152.Fa x No / Fa y No \\*(Ba 153.Sm on 154= 1551/2 156then 157.Fa n 158is even. Consequently 159the remainder is computed exactly and 160.Sm off 161.Pf \\*(Ba Fa r No \\*(Ba 162.Sm on 163\*(Le 164.Sm off 165.Pf \\*(Ba Fa y No \\*(Ba/2 . 166.Sm on 167But 168.Fn remainder x 0 169and 170.Fn remainder \*(If 0 171are invalid operations that produce a \*(Na. 172.Pp 173.Fn scalbn 174and 175.Fn scalbnf 176return 177.Fa x Ns \(**(2** Ns Fa n ) 178computed by exponent manipulation. 179.Sh SEE ALSO 180.Xr math 3 181.Sh HISTORY 182The 183.Nm ieee 184functions appeared in 185.Bx 4.3 . 186The 187.Fn copysignl 188function first appeared in 189.Fx 5.3 . 190.Sh STANDARDS 191.St -ieee754 192