ec79bc0da9
- It was added to libc instead of libm. Hopefully no programs rely on this mistake. - It didn't work properly on large long doubles because its argument was converted to type double, resulting in undefined behavior.
58 lines
1.9 KiB
Groff
58 lines
1.9 KiB
Groff
.\" 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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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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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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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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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 July 18, 2004
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.Dt SIGNBIT 3
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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 libm
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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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.Fa x
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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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