1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
.\" $OpenBSD: fegetround.3,v 1.3 2013/06/05 03:40:26 tedu Exp $
.\"
.\" Copyright (c) 2011 Martynas Venckus <martynas@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: June 5 2013 $
.Dt FEGETROUND 3
.Os
.Sh NAME
.Nm fegetround ,
.Nm fesetround
.Nd control floating-point rounding direction modes
.Sh SYNOPSIS
.In fenv.h
.Ft int
.Fn fegetround void
.Ft int
.Fn fesetround "int round"
.Sh DESCRIPTION
These functions provide control of floating-point rounding direction
modes.
The
.Fa round
input argument is a value specifying a rounding direction mode and
containing any of the values listed below.
.Bl -tag -width ".Dv FE_TOWARDZERO"
.It Dv FE_TONEAREST
Results are rounded to the closest representable value.
If the exact result is exactly half way between two representable
values, the value whose last binary digit is even (zero) is chosen.
This is the default mode.
.It Dv FE_DOWNWARD
Results are rounded towards negative \*[If].
.It Dv FE_UPWARD
Results are rounded towards positive \*[If].
.It Dv FE_TOWARDZERO
Results are rounded towards zero.
.El
.Pp
The
.Fn fegetround
function gets the current rounding direction.
.Pp
The
.Fn fesetround
function establishes the rounding direction represented by
.Pa round .
If the argument is not equal to the value of a rounding direction
macro, the rounding direction is not changed.
.Sh RETURN VALUES
The
.Fn fegetround
function returns the current rounding direction.
The
.Fn fesetround
function return zero on success, and non-zero if an error occurred.
.Sh SEE ALSO
.Xr feclearexcept 3 ,
.Xr feenableexcept 3 ,
.Xr fegetenv 3
.Sh STANDARDS
The
.Fn fegetround
and
.Fn fesetround
functions conform to
.St -isoC-99 .
.Sh HISTORY
These functions first appeared in
.Ox 5.0 .
|
