xref: /freebsd/lib/msun/man/remainder.3 (revision c7392feeccfd2d71cb7751bd31c1483aa35a7633)
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.\" 4. 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.\" $FreeBSD$
30.\"
31.Dd March 30, 2008
32.Dt REMAINDER 3
33.Os
34.Sh NAME
35.Nm remainder ,
36.Nm remainderf ,
37.Nm remainderl ,
38.Nm remquo ,
39.Nm remquof ,
40.Nm remquol
41.Nd minimal residue functions
42.Sh LIBRARY
43.Lb libm
44.Sh SYNOPSIS
45.In math.h
46.Ft double
47.Fn remainder "double x" "double y"
48.Ft float
49.Fn remainderf "float x" "float y"
50.Ft long double
51.Fn remainderl "long double x" "long double y"
52.Ft double
53.Fn remquo "double x" "double y" "int *quo"
54.Ft float
55.Fn remquof "float x" "float y" "int *quo"
56.Ft long double
57.Fn remquol "long double x" "long double y" "int *quo"
58.Sh DESCRIPTION
59.Fn remainder ,
60.Fn remainderf ,
61.Fn remainderl ,
62.Fn remquo ,
63.Fn remquof ,
64and
65.Fn remquol
66return the remainder
67.Fa r
68:=
69.Fa x
70\-
71.Fa n\(**y
72where
73.Fa n
74is the integer nearest the exact value of
75.Bk -words
76.Fa x Ns / Ns Fa y ;
77.Ek
78moreover if
79.Pf \\*(Ba Fa n
80\-
81.Sm off
82.Fa x No / Fa y No \\*(Ba
83.Sm on
84=
851/2
86then
87.Fa n
88is even.
89Consequently
90the remainder is computed exactly and
91.Sm off
92.Pf \\*(Ba Fa r No \\*(Ba
93.Sm on
94\*(Le
95.Sm off
96.Pf \\*(Ba Fa y No \\*(Ba/2 .
97.Sm on
98But attempting to take the remainder when
99.Fa y
100is 0 or
101.Fa x
102is \*(Pm\*(If is an invalid operation that produces a \*(Na.
103.Pp
104The
105.Fn remquo ,
106.Fn remquof ,
107and
108.Fn remquol
109functions also store the last
110.Va k
111bits of
112.Fa n
113in the location pointed to by
114.Fa quo ,
115provided that
116.Fa n
117exists.
118The number of bits
119.Va k
120is platform-specific, but is guaranteed to be at least 3.
121.Sh SEE ALSO
122.Xr fmod 3 ,
123.Xr ieee 3 ,
124.Xr math 3
125.Sh STANDARDS
126The
127.Fn remainder ,
128.Fn remainderf ,
129.Fn remainderl ,
130.Fn remquo ,
131.Fn remquof ,
132and
133.Fn remquol
134routines conform to
135.St -isoC-99 .
136The remainder is as defined in
137.St -ieee754 .
138.Sh HISTORY
139The
140.Fn remainder
141and
142.Fn remainderf
143functions appeared in
144.Bx 4.3
145and
146.Fx 2.0 ,
147respectively.
148The
149.Fn remquo
150and
151.Fn remquof
152functions were added in
153.Fx 6.0 ,
154and
155.Fn remainderl
156and
157.Fn remquol
158were added in
159.Fx 8.0 .
160