2003-02-11 21:56:21 +00:00
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.\" Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd February 11, 2003
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2003-02-12 03:29:39 +00:00
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.Dt SIGNBIT 3
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2003-02-11 21:56:21 +00:00
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.Os
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.Sh NAME
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.Nm signbit
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.Nd "determine whether a floating-point number's sign is negative"
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In math.h
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.Ft int
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.Fn signbit "real-floating x"
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.Sh DESCRIPTION
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The
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.Fn signbit
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macro takes an argument of
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2003-02-24 22:53:26 +00:00
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.Fa x
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2003-02-11 21:56:21 +00:00
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and returns non-zero if the value of its sign is negative, otherwise 0.
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.Sh SEE ALSO
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.Xr fpclassify 3 ,
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.Xr math 3
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.Sh STANDARDS
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The
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.Fn signbit
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macro conforms to
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.St -isoC-99 .
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.Sh HISTORY
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The
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.Fn signbit
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macro was added in
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.Fx 5.1 .
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