.\"	$OpenBSD: fegetround.3,v 1.2 2011/05/26 15:42:27 jmc Exp $
.\"
.\" Copyright (c) 2011 Martynas Venckus <martynas@openbsd.org>
.\"
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.Dd $Mdocdate: May 26 2011 $
.Dt FEGETROUND 3
.Os
.Sh NAME
.Nm fegetround ,
.Nm fesetround
.Nd control floating-point rounding direction modes
.Sh SYNOPSIS
.Fd #include <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 .