.\"	$OpenBSD: fpgetmask.3,v 1.9 2013/06/05 03:39:22 tedu Exp $
.\"	$NetBSD: fpgetmask.3,v 1.3 2001/09/16 02:57:03 wiz Exp $
.\"
.\" Copyright (c) 1999 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Ross Harvey.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd $Mdocdate: June 5 2013 $
.Dt FPGETMASK 3
.Os
.Sh NAME
.Nm fpgetmask ,
.Nm fpgetround ,
.Nm fpgetsticky ,
.Nm fpsetmask ,
.Nm fpsetround ,
.Nm fpsetsticky
.Nd IEEE FP mode control
.Sh SYNOPSIS
.In ieeefp.h
.Ft fp_except
.Fn fpgetmask void
.Ft fp_rnd
.Fn fpgetround void
.Ft fp_except
.Fn fpgetsticky void
.Ft fp_except
.Fn fpsetmask fp_except\ mask
.Ft fp_rnd
.Fn fpsetround fp_rnd\ rnd_dir
.Ft fp_except
.Fn fpsetsticky fp_except\ sticky
.Sh DESCRIPTION
A rounding mode is one of
.Dv FP_RZ , FP_RM , FP_RN ,
or
.Dv FP_RP ,
for rounding towards zero, rounding
.Pq Em Minus infinity
down, rounding to
.Em nearest ,
and rounding
.Pq Em Plus infinity
up.
The default mode is
.Dv FP_RN .
.Pp
An
.Ft fp_except
value is a bitmask specifying an exception type and containing any of
the values listed below.
.Bl -column FP_X_UFLxx -offset indent
.It Dv FP_X_INV Ta Invalid\ Operation
.It Dv FP_X_DZ Ta Division\ by\ zero
.It Dv FP_X_OFL Ta Overflow
.It Dv FP_X_UFL Ta Underflow
.It Dv FP_X_IMP Ta Imprecision (inexact)
.It Dv FP_X_DNML Ta Denormalization Pq amd64 and i386 only
.El
.Pp
The
.Fn fpsetmask
function will cause future operations with the specified result status to
raise the
.Dv SIGFPE
exception.
The
.Fn fpsetround
function will cause future operations to use the specified dynamic mode.
.Bl -tag -width Note:x
.It Em Note :
On some architectures, instructions can optionally specify static
rounding modes and exception enables that will supersede the specified
dynamic mode.
On other architectures, these features may not be fully supported.
.El
.Pp
The
.Fn fpsetsticky
function will set or clear the specified exception history bits.
.Sh RETURN VALUES
The
.Fn fpgetround
and
.Fn fpsetround
functions return the
.Pq previous
rounding mode.
The
.Fn fpgetmask ,
.Fn fpsetmask ,
.Fn fpgetsticky ,
and
.Fn fpsetsticky
functions return the
.Pq previous
exception mask and exception history bits.
.Sh SEE ALSO
.Xr sigaction 2