1.\" $NetBSD: nan.3,v 1.4 2011/06/10 14:10:18 njoly Exp $ 2.\" 3.\" Copyright (c) 2006 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Klaus Klein. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28.\" POSSIBILITY OF SUCH DAMAGE. 29.\" 30.Dd March 15, 2006 31.Dt NAN 3 32.Os 33.Sh NAME 34.Nm nan , 35.Nm nanf , 36.Nm nanl 37.Nd return quiet NaN 38.Sh LIBRARY 39.Lb libm 40.Sh SYNOPSIS 41.In math.h 42.Ft double 43.Fn nan "const char *tagp" 44.Ft float 45.Fn nanf "const char *tagp" 46.Ft long double 47.Fn nanl "const char *tagp" 48.Sh DESCRIPTION 49The call 50.Fn nan "\*qn-char-sequence\*q" 51is equivalent to the call 52.Fn strod "\*qNAN(n-char-sequence)\*q" "NULL" . 53The call 54.Fn nan "\*q\*q" 55is equivalent to the call 56.Fn strod "\*qNAN()\*q" "NULL" . 57.Pp 58The 59.Fn nanf 60and 61.Fn nanl 62functions are equivalent to 63.Fn nan 64but substituting 65.Fn strtof 66and 67.Fn strtold , 68respectively. 69.Sh RETURN VALUES 70.Ss IEEE 754 71The 72.Fn nan , 73.Fn nanf , 74and 75.Fn nanl 76functions return a quiet NaN as specified by 77.Fa tagp . 78.Ss VAX 79The 80.Fn nan , 81.Fn nanf , 82and 83.Fn nanl 84functions return zero. 85.Sh SEE ALSO 86.Xr math 3 , 87.Xr strtod 3 88.Sh STANDARDS 89The 90.Fn nan , 91.Fn nanf , 92and 93.Fn nanl 94functions conform to 95.St -isoC-99 . 96