xref: /freebsd/lib/libc/gen/frexp.3 (revision fcb560670601b2a4d87bb31d7531c8dcc37ee71b)
1.\" Copyright (c) 1991, 1993
2.\"	The Regents of the University of California.  All rights reserved.
3.\"
4.\" This code is derived from software contributed to Berkeley by
5.\" the American National Standards Committee X3, on Information
6.\" Processing Systems.
7.\"
8.\" Redistribution and use in source and binary forms, with or without
9.\" modification, are permitted provided that the following conditions
10.\" are met:
11.\" 1. Redistributions of source code must retain the above copyright
12.\"    notice, this list of conditions and the following disclaimer.
13.\" 2. Redistributions in binary form must reproduce the above copyright
14.\"    notice, this list of conditions and the following disclaimer in the
15.\"    documentation and/or other materials provided with the distribution.
16.\" 4. Neither the name of the University nor the names of its contributors
17.\"    may be used to endorse or promote products derived from this software
18.\"    without specific prior written permission.
19.\"
20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30.\" SUCH DAMAGE.
31.\"
32.\"     @(#)frexp.3	8.1 (Berkeley) 6/4/93
33.\" $FreeBSD$
34.\"
35.Dd March 4, 2005
36.Dt FREXP 3
37.Os
38.Sh NAME
39.Nm frexp ,
40.Nm frexpf ,
41.Nm frexpl
42.Nd convert floating-point number to fractional and integral components
43.Sh LIBRARY
44.Lb libm
45.Sh SYNOPSIS
46.In math.h
47.Ft double
48.Fn frexp "double value" "int *exp"
49.Ft float
50.Fn frexpf "float value" "int *exp"
51.Ft long double
52.Fn frexpl "long double value" "int *exp"
53.Sh DESCRIPTION
54The
55.Fn frexp ,
56.Fn frexpf
57and
58.Fn frexpl
59functions break a floating-point number into a normalized
60fraction and an integral power of 2.
61They store the integer in the
62.Vt int
63object pointed to by
64.Fa exp .
65.Sh RETURN VALUES
66These functions return the value
67.Va x ,
68such that
69.Va x
70is a
71.Vt double
72with magnitude in the interval
73.Eo [ 1/2 , 1 Ec )
74or zero, and
75.Fa value
76equals
77.Va x
78times 2 raised to the power
79.Fa *exp .
80If
81.Fa value
82is zero, both parts of the result are zero.
83.Sh SEE ALSO
84.Xr ldexp 3 ,
85.Xr math 3 ,
86.Xr modf 3
87.Sh STANDARDS
88The
89.Fn frexp ,
90.Fn frexpf ,
91and
92.Fn frexpl
93functions conform to
94.St -isoC-99 .
95