90 lines
2.7 KiB
Groff
90 lines
2.7 KiB
Groff
.\" $NetBSD: ldexp.3,v 1.1 2006/07/03 16:03:56 drochner Exp $
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.\"
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.\" Copyright (c) 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" the American National Standards Committee X3, on Information
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.\" Processing Systems.
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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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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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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.\" @(#)ldexp.3 8.2 (Berkeley) 4/19/94
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.\"
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.Dd March 21, 2006
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.Dt LDEXP 3
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.Os
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.Sh NAME
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.Nm ldexp
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.Nd multiply floating-point number by integral power of 2
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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 ldexp "double x" "int exp"
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.Ft float
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.Fn ldexpf "float x" "int exp"
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.Sh DESCRIPTION
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The
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.Fn ldexp
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function multiplies a floating-point number by an integral
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power of 2.
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.Sh RETURN VALUES
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The
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.Fn ldexp
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function returns the value of
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.Fa x
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times 2 raised to the power
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.Fa exp .
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.Pp
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If the input
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.Va x
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is a NaN, infinity, or 0.0, it is returned unchanged.
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.Pp
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If the result would cause an overflow,
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the global variable
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.Va errno
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is set to
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.Er ERANGE
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and infinity is returned, with the same sign as
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.Fa x .
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.Pp
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If the result would cause underflow to 0.0,
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the global variable
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.Va errno
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is set to
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.Er ERANGE
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and the value 0.0 is returned.
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.Sh SEE ALSO
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.Xr frexp 3 ,
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.Xr math 3 ,
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.Xr modf 3
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.Sh STANDARDS
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The
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.Fn ldexp
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function conforms to
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.St -ansiC .
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