1.\" $OpenBSD: fpclassify.3,v 1.5 2016/03/10 08:38:34 jmc Exp $ 2.\" 3.\" Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org> 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 AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.\" $FreeBSD: src/lib/libc/gen/fpclassify.3,v 1.6 2005/01/27 05:46:16 das Exp $ 28.\" 29.Dd $Mdocdate: March 10 2016 $ 30.Dt FPCLASSIFY 3 31.Os 32.Sh NAME 33.Nm fpclassify , 34.Nm isfinite , 35.Nm isinf , 36.Nm isnan , 37.Nm isnormal , 38.Nm signbit , 39.Nm finite , 40.Nm finitef , 41.Nm isinff , 42.Nm isnanf 43.Nd classify a floating-point number 44.Sh SYNOPSIS 45.In math.h 46.Ft int 47.Fn fpclassify "real-floating x" 48.Ft int 49.Fn isfinite "real-floating x" 50.Ft int 51.Fn isinf "real-floating x" 52.Ft int 53.Fn isnan "real-floating x" 54.Ft int 55.Fn isnormal "real-floating x" 56.Ft int 57.Fn signbit "real-floating x" 58.Sh DESCRIPTION 59The 60.Fn fpclassify 61macro takes an argument of 62.Fa x 63and returns one of the following manifest constants: 64.Pp 65.Bl -tag -width "FP_SUBNORMALXXX" -offset indent -compact 66.It Dv FP_INFINITE 67Indicates that 68.Fa x 69is an infinite number. 70.It Dv FP_NAN 71Indicates that 72.Fa x 73is not a number (NaN). 74.It Dv FP_NORMAL 75Indicates that 76.Fa x 77is a normalized number. 78.It Dv FP_SUBNORMAL 79Indicates that 80.Fa x 81is a denormalized number. 82.It Dv FP_ZERO 83Indicates that 84.Fa x 85is zero (0 or \-0). 86.El 87.Pp 88The 89.Fn isfinite 90macro returns a non-zero value if and only if its argument has 91a finite (zero, subnormal, or normal) value. 92.Pp 93The 94.Fn isinf , 95.Fn isnan , 96and 97.Fn isnormal 98macros return non-zero if and only if 99.Fa x 100is an infinity, NaN, 101or a non-zero normalized number, respectively. 102.Pp 103The 104.Fn signbit 105macro takes an argument of 106.Fa x 107and returns non-zero if the value of its sign is negative, otherwise 0. 108.Sh SEE ALSO 109.Xr isgreater 3 110.Sh STANDARDS 111The 112.Fn fpclassify , 113.Fn isfinite , 114.Fn isinf , 115.Fn isnan , 116.Fn isnormal , 117and 118.Fn signbit 119macros conform to 120.St -isoC-99 . 121.Pp 122The symbols 123.Fn isinff , 124and 125.Fn isnanf 126are provided as compatibility aliases to 127.Fn isinf , 128and 129.Fn isnan , 130respectively, and their uses are deprecated. 131Similarly, 132.Fn finite 133and 134.Fn finitef 135are deprecated versions of 136.Fn isfinite . 137.Sh HISTORY 138The 139.Fn fpclassify , 140.Fn isfinite , 141.Fn isinf , 142.Fn isnan , 143.Fn isnormal , 144and 145.Fn signbit 146macros were added in 147.Ox 4.4 . 148.Bx 3 149introduced 150.Fn isinf 151and 152.Fn isnan 153functions, which accepted 154.Vt double 155arguments; these have been superseded by the macros 156described above. 157