1.\" $NetBSD: signbit.3,v 1.2 2004/01/15 20:31:40 wiz Exp $ 2.\" 3.\" Copyright (c) 2003 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.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the NetBSD 20.\" Foundation, Inc. and its contributors. 21.\" 4. Neither the name of The NetBSD Foundation nor the names of its 22.\" contributors may be used to endorse or promote products derived 23.\" from this software without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 26.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 29.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35.\" POSSIBILITY OF SUCH DAMAGE. 36.\" 37.Dd October 29, 2003 38.Dt SIGNBIT 3 39.Os 40.Sh NAME 41.Nm signbit 42.Nd test sign 43.Sh LIBRARY 44.Lb libc 45.Sh SYNOPSIS 46.In math.h 47.Ft int 48.Fn signbit "real-floating x" 49.Sh DESCRIPTION 50The 51.Fn signbit 52macro determines whether the sign of its argument value 53.Fa x 54is negative. 55An argument represented in a format wider than its semantic type is 56converted to its semantic type first. 57The determination is then based on the type of the argument. 58.Ss IEEE754 59The sign is determined for all values, including infinities, zeroes, 60and NaNs 61.Ss VAX 62The sign is determined for finites, true zeros, and dirty zeroes; 63for ROPs the sign is reported negative. 64.Sh RETURN VALUES 65The 66.Fn signbit 67macro returns a non-zero value if the sign of its value 68.Fa x 69is negative. 70Otherwise 0 is returned. 71.Sh ERRORS 72No errors are defined. 73.Sh SEE ALSO 74.Xr fpclassify 3 , 75.Xr isfinite 3 , 76.Xr isnormal 3 , 77.Xr math 3 78.Sh STANDARDS 79The 80.Fn signbit 81macro conforms to 82.St -isoC-99 . 83