xref: /freebsd/lib/msun/man/remainder.3 (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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 24, 2005
32.Dt REMAINDER 3
33.Os
34.Sh NAME
35.Nm remainder ,
36.Nm remainderf ,
37.Nm remquo ,
38.Nm remquof
39.Nd minimal residue functions
40.Sh LIBRARY
41.Lb libm
42.Sh SYNOPSIS
43.In math.h
44.Ft double
45.Fn remainder "double x" "double y"
46.Ft float
47.Fn remainderf "float x" "float y"
48.Ft double
49.Fn remquo "double x" "double y" "int *quo"
50.Ft float
51.Fn remquof "float x" "float y" "int *quo"
52.Sh DESCRIPTION
53.Fn remainder ,
54.Fn remainderf ,
55.Fn remquo ,
56and
57.Fn remquof
58return the remainder
59.Fa r
60:=
61.Fa x
62\-
63.Fa n\(**y
64where
65.Fa n
66is the integer nearest the exact value of
67.Bk -words
68.Fa x Ns / Ns Fa y ;
69.Ek
70moreover if
71.Pf \\*(Ba Fa n
72\-
73.Sm off
74.Fa x No / Fa y No \\*(Ba
75.Sm on
76=
771/2
78then
79.Fa n
80is even.
81Consequently
82the remainder is computed exactly and
83.Sm off
84.Pf \\*(Ba Fa r No \\*(Ba
85.Sm on
86\*(Le
87.Sm off
88.Pf \\*(Ba Fa y No \\*(Ba/2 .
89.Sm on
90But attempting to take the remainder when
91.Fa y
92is 0 or
93.Fa x
94is \*(Pm\*(If is an invalid operation that produces a \*(Na.
95.Pp
96The
97.Fn remquo
98and
99.Fn remquof
100functions also store the last
101.Va k
102bits of
103.Fa n
104in the location pointed to by
105.Fa quo ,
106provided that
107.Fa n
108exists.
109The number of bits
110.Va k
111is platform-specific, but is guaranteed to be at least 3.
112.Sh SEE ALSO
113.Xr fmod 3 ,
114.Xr ieee 3 ,
115.Xr math 3
116.Sh STANDARDS
117The
118.Fn remainder ,
119.Fn remainderf ,
120.Fn remquo ,
121and
122.Fn remquof
123routines conform to
124.St -isoC-99 .
125The remainder is as defined in
126.St -ieee754 .
127.Sh HISTORY
128The
129.Fn remainder
130and
131.Fn remainderf
132functions appeared in
133.Bx 4.3
134and
135.Fx 2.0 ,
136respectively.
137The
138.Fn remquo
139and
140.Fn remquof
141functions were added in
142.Fx 6.0 .
143