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.\" $NetBSD: pow.3,v 1.1 2011/09/17 10:51:53 jruoho Exp $
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.\"
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.\" Copyright (c) 2011 Jukka Ruohonen <jruohonen@iki.fi>
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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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd September 13, 2011
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.Dt POW 3
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.Os
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.Sh NAME
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.Nm pow ,
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.Nm powf
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.Nd power functions
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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 double
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.Fn pow "double x" "double y"
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.Ft float
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.Fn powf "float x" "float y"
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.Sh DESCRIPTION
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The
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.Fn pow
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family of functions return
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.Fa x
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raised to the power of
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.Fa y .
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.Pp
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If
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.Fa x
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is negative and
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.Fa y
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is not an integer, the global variable
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.Va errno
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is set to
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.Er EDOM ,
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and on
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.Tn VAX
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a reserved operand fault is generated.
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A portable application should nevertheless ensure that
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.Fa y
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is an integer value whenever
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.Fa x
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is negative.
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.Sh RETURN VALUES
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.\"
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.\" XXX: List also the special return values?
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.\"
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Upon successful completion, the described functions return
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.Fa x^y .
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.Sh SEE ALSO
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.Xr exp 3 ,
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.Xr log 3
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.Sh STANDARDS
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The described functions conform to
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.St -isoC-99 .
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.Sh HISTORY
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The history of the power functions dates back to
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.At v6 .
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