xref: /freebsd/lib/msun/man/remainder.3 (revision 2008043f386721d58158e37e0d7e50df8095942d)
1.\" Copyright (c) 1985, 1991 Regents of the University of California.
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\"    notice, this list of conditions and the following disclaimer.
9.\" 2. Redistributions in binary form must reproduce the above copyright
10.\"    notice, this list of conditions and the following disclaimer in the
11.\"    documentation and/or other materials provided with the distribution.
12.\" 3. Neither the name of the University nor the names of its contributors
13.\"    may be used to endorse or promote products derived from this software
14.\"    without specific prior written permission.
15.\"
16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26.\" SUCH DAMAGE.
27.\"
28.\"     from: @(#)ieee.3	6.4 (Berkeley) 5/6/91
29.\"
30.Dd March 30, 2008
31.Dt REMAINDER 3
32.Os
33.Sh NAME
34.Nm remainder ,
35.Nm remainderf ,
36.Nm remainderl ,
37.Nm remquo ,
38.Nm remquof ,
39.Nm remquol
40.Nd minimal residue functions
41.Sh LIBRARY
42.Lb libm
43.Sh SYNOPSIS
44.In math.h
45.Ft double
46.Fn remainder "double x" "double y"
47.Ft float
48.Fn remainderf "float x" "float y"
49.Ft long double
50.Fn remainderl "long double x" "long double y"
51.Ft double
52.Fn remquo "double x" "double y" "int *quo"
53.Ft float
54.Fn remquof "float x" "float y" "int *quo"
55.Ft long double
56.Fn remquol "long double x" "long double y" "int *quo"
57.Sh DESCRIPTION
58.Fn remainder ,
59.Fn remainderf ,
60.Fn remainderl ,
61.Fn remquo ,
62.Fn remquof ,
63and
64.Fn remquol
65return the remainder
66.Fa r
67:=
68.Fa x
69\-
70.Fa n\(**y
71where
72.Fa n
73is the integer nearest the exact value of
74.Bk -words
75.Fa x Ns / Ns Fa y ;
76.Ek
77moreover if
78.Pf \*(Ba Fa n
79\-
80.Sm off
81.Fa x No / Fa y No \*(Ba
82.Sm on
83=
841/2
85then
86.Fa n
87is even.
88Consequently
89the remainder is computed exactly and
90.Sm off
91.Pf \*(Ba Fa r No \*(Ba
92.Sm on
93\*(Le
94.Sm off
95.Pf \*(Ba Fa y No \*(Ba/2 .
96.Sm on
97But attempting to take the remainder when
98.Fa y
99is 0 or
100.Fa x
101is \*(Pm\*(If is an invalid operation that produces a \*(Na.
102.Pp
103The
104.Fn remquo ,
105.Fn remquof ,
106and
107.Fn remquol
108functions also store the last
109.Va k
110bits of
111.Fa n
112in the location pointed to by
113.Fa quo ,
114provided that
115.Fa n
116exists.
117The number of bits
118.Va k
119is platform-specific, but is guaranteed to be at least 3.
120.Sh SEE ALSO
121.Xr fmod 3 ,
122.Xr ieee 3 ,
123.Xr math 3
124.Sh STANDARDS
125The
126.Fn remainder ,
127.Fn remainderf ,
128.Fn remainderl ,
129.Fn remquo ,
130.Fn remquof ,
131and
132.Fn remquol
133routines conform to
134.St -isoC-99 .
135The remainder is as defined in
136.St -ieee754 .
137.Sh HISTORY
138The
139.Fn remainder
140and
141.Fn remainderf
142functions appeared in
143.Bx 4.3
144and
145.Fx 2.0 ,
146respectively.
147The
148.Fn remquo
149and
150.Fn remquof
151functions were added in
152.Fx 6.0 ,
153and
154.Fn remainderl
155and
156.Fn remquol
157were added in
158.Fx 8.0 .
159