xref: /freebsd/lib/msun/man/remainder.3 (revision 053d1689b12d6470404e151104c622c8fdbc398e)
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32.\"     from: @(#)ieee.3	6.4 (Berkeley) 5/6/91
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35.Dd March 24, 2005
36.Dt REMAINDER 3
37.Os
38.Sh NAME
39.Nm remainder ,
40.Nm remainderf ,
41.Nm remquo ,
42.Nm remquof
43.Nd minimal residue functions
44.Sh LIBRARY
45.Lb libm
46.Sh SYNOPSIS
47.In math.h
48.Ft double
49.Fn remainder "double x" "double y"
50.Ft float
51.Fn remainderf "float x" "float 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.Sh DESCRIPTION
57.Fn remainder ,
58.Fn remainderf ,
59.Fn remquo ,
60and
61.Fn remquof
62return the remainder
63.Fa r
64:=
65.Fa x
66\-
67.Fa n\(**y
68where
69.Fa n
70is the integer nearest the exact value of
71.Bk -words
72.Fa x Ns / Ns Fa y ;
73.Ek
74moreover if
75.Pf \\*(Ba Fa n
76\-
77.Sm off
78.Fa x No / Fa y No \\*(Ba
79.Sm on
80=
811/2
82then
83.Fa n
84is even.
85Consequently
86the remainder is computed exactly and
87.Sm off
88.Pf \\*(Ba Fa r No \\*(Ba
89.Sm on
90\*(Le
91.Sm off
92.Pf \\*(Ba Fa y No \\*(Ba/2 .
93.Sm on
94But attempting to take the remainder when
95.Fa y
96is 0 or
97.Fa x
98is \*(Pm\*(If is an invalid operation that produces a \*(Na.
99.Pp
100The
101.Fn remquo
102and
103.Fn remquof
104functions also store the last
105.Va k
106bits of
107.Fa n
108in the location pointed to by
109.Fa quo ,
110provided that
111.Fa n
112exists.
113The number of bits
114.Va k
115is platform-specific, but is guaranteed to be at least 3.
116.Sh SEE ALSO
117.Xr fmod 3 ,
118.Xr ieee 3 ,
119.Xr math 3
120.Sh STANDARDS
121The
122.Fn remainder ,
123.Fn remainderf ,
124.Fn remquo ,
125and
126.Fn remquof
127routines conform to
128.St -isoC-99 .
129The remainder is as defined in
130.St -ieee754 .
131.Sh HISTORY
132The
133.Fn remainder
134and
135.Fn remainderf
136functions appeared in
137.Bx 4.3
138and
139.Fx 2.0 ,
140respectively.
141The
142.Fn remquo
143and
144.Fn remquof
145functions were added in
146.Fx 5.5 .
147