106 lines
3.1 KiB
Groff
106 lines
3.1 KiB
Groff
.\" $NetBSD: ldexp.3,v 1.5 2016/03/17 18:29:59 nros 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 17, 2016
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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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.Nm ldexpf ,
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.Nm ldexpl
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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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.Ft long double
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.Fn ldexpl "long double x" "int exp"
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.Sh DESCRIPTION
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The
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.Fn ldexp
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family of functions compute
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.Bd -ragged -offset indent
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.Va x
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*
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2^\fIexp\fR
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.Ed
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.Pp
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for a real floating-point number
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.Fa x .
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.Sh RETURN VALUES
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The functions return 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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Otherwise the following may occur:
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.Bl -enum -offset indent
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.It
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If
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.Fa x
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is \*(Na, a \*(Na is returned.
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.It
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If
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.Fa exp
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is zero or
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.Fa x
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is either \*(Pm 0 or \*(Pm\[if],
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.Fa x
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is returned.
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.It
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If the call would cause an overflow, a range error occurs and either
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.Dv \*(Pm\*HHUGE_VAL ,
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.Dv \*(Pm\*HHUGE_VALF ,
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or
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.Dv \*(Pm\*HHUGE_VALL
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is returned, depending on the sign of
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.Fa x
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and the type of the return value.
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.It
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If an underflow would be caused by the correct value,
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and the value is not representable, either 0.0 or
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an implementation-defined value is returned.
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.El
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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 described functions conform to
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.St -isoC-99 .
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