1.\" $NetBSD: isinf.3,v 1.12 2004/03/04 23:47:56 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.\" @(#)isinf.3 8.2 (Berkeley) 1/29/94 31.\" 32.Dd March 5, 2004 33.Dt ISINF 3 34.Os 35.Sh NAME 36.Nm isinf 37.Nd test for infinity 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In math.h 42.Ft int 43.Fn isinf "real-floating x" 44.Sh DESCRIPTION 45The 46.Fn isinf 47macro determines whether its argument 48.Fa x 49is an infinity (positive or negative). 50An argument represented in a format wider than its semantic type is 51converted to its semantic type first. 52The determination is then based on the type of the argument. 53.Ss IEEE 754 54It is determined whether the value of 55.Fa x 56is an infinity. 57.Ss VAX 58Infinities are not supported. 59.Sh RETURN VALUES 60The 61.Fn isinf 62macro returns a non-zero value if the value of 63.Fa x 64is an infinity. 65Otherwise 0 is returned. 66.Sh SEE ALSO 67.Xr fpclassify 3 , 68.Xr isfinite 3 , 69.Xr isinff 3 , 70.Xr isnan 3 , 71.Xr isnanf 3 , 72.Xr isnormal 3 , 73.Xr math 3 , 74.Xr signbit 3 75.Rs 76.%T "IEEE Standard for Binary Floating-Point Arithmetic" 77.%Q ANSI 78.%R Std 754-1985 79.Re 80.Sh STANDARDS 81The 82.Fn isinf 83macro conforms to 84.St -isoC-99 . 85