1.\" Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.Dd July 18, 2004 26.Dt SIGNBIT 3 27.Os 28.Sh NAME 29.Nm signbit 30.Nd "determine whether a floating-point number's sign is negative" 31.Sh LIBRARY 32.Lb libm 33.Sh SYNOPSIS 34.In math.h 35.Ft int 36.Fn signbit "real-floating x" 37.Sh DESCRIPTION 38The 39.Fn signbit 40macro takes an argument of 41.Fa x 42and returns non-zero if the value of its sign is negative, otherwise 0. 43.Sh SEE ALSO 44.Xr fpclassify 3 , 45.Xr math 3 46.Sh STANDARDS 47The 48.Fn signbit 49macro conforms to 50.St -isoC-99 . 51.Sh HISTORY 52The 53.Fn signbit 54macro was added in 55.Fx 5.1 . 56