1.\" $NetBSD: isnan.3,v 1.2 2004/03/04 23:49:31 wiz Exp $ 2.\" 3.\" Copyright (c) 1991, 1993 4.\" The Regents of the University of California. 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.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" From: @(#)isinf.3 8.2 (Berkeley) 1/29/94 31.\" from: NetBSD: isinf.3,v 1.10 2003/08/07 16:42:52 agc Exp 32.\" 33.Dd March 5, 2004 34.Dt ISNAN 3 35.Os 36.Sh NAME 37.Nm isnan 38.Nd test for not-a-number 39.Sh LIBRARY 40.Lb libc 41.Sh SYNOPSIS 42.In math.h 43.Ft int 44.Fn isnan "real-floating x" 45.Sh DESCRIPTION 46The 47.Fn isnan 48macro determines whether its argument 49.Fa x 50is not-a-number 51.Pq Dq NaN . 52An argument represented in a format wider than its semantic type is 53converted to its semantic type first. 54The determination is then based on the type of the argument. 55.Ss IEEE 754 56It is determined whether the value of 57.Fa x 58is a NaN. 59.Ss VAX 60NaNs are not supported. 61.Sh RETURN VALUES 62The 63.Fn isnan 64macro returns a non-zero value if the value of 65.Fa x 66is a NaN. 67Otherwise 0 is returned. 68.Sh SEE ALSO 69.Xr fpclassify 3 , 70.Xr isfinite 3 , 71.Xr isinf 3 , 72.Xr isinff 3 , 73.Xr isnanf 3 , 74.Xr isnormal 3 , 75.Xr math 3 , 76.Xr signbit 3 77.Rs 78.%T "IEEE Standard for Binary Floating-Point Arithmetic" 79.%Q ANSI 80.%R Std 754-1985 81.Re 82.Sh STANDARDS 83The 84.Fn isnan 85macro conforms to 86.St -isoC-99 . 87