140 lines
4.1 KiB
Groff
140 lines
4.1 KiB
Groff
.\" Copyright (c) 2004 David Schultz <das@FreeBSD.org>
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" 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 AUTHOR 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 AUTHOR 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.
|
|
.\"
|
|
.\" $FreeBSD: src/lib/msun/man/feclearexcept.3,v 1.3 2005/01/14 09:12:05 ru Exp $
|
|
.\"
|
|
.Dd May 8, 2004
|
|
.Dt FECLEAREXCEPT 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm feclearexcept ,
|
|
.Nm fegetexceptflag ,
|
|
.Nm feraiseexcept ,
|
|
.Nm fesetexceptflag ,
|
|
.Nm fetestexcept
|
|
.Nd floating-point exception flag manipulation
|
|
.Sh LIBRARY
|
|
.Lb libm
|
|
.Sh SYNOPSIS
|
|
.In fenv.h
|
|
.Fd "#pragma STDC FENV_ACCESS ON"
|
|
.Ft int
|
|
.Fn feclearexcept "int excepts"
|
|
.Ft int
|
|
.Fn fegetexceptflag "fexcept_t *flagp" "int excepts"
|
|
.Ft int
|
|
.Fn feraiseexcept "int excepts"
|
|
.Ft int
|
|
.Fn fesetexceptflag "const fexcept_t *flagp" "int excepts"
|
|
.Ft int
|
|
.Fn fetestexcept "int excepts"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn feclearexcept
|
|
routine clears the floating-point exception flags specified by
|
|
.Fa excepts ,
|
|
whereas
|
|
.Fn feraiseexcept
|
|
raises the specified exceptions.
|
|
Raising an exception causes the corresponding flag to be set,
|
|
and a
|
|
.Dv SIGFPE
|
|
is delivered to the process if the exception is unmasked.
|
|
.Pp
|
|
The
|
|
.Fn fetestexcept
|
|
function determines which flags are currently set, of those specified by
|
|
.Fa excepts .
|
|
.Pp
|
|
The
|
|
.Fn fegetexceptflag
|
|
function stores the state of the exception flags specified in
|
|
.Fa excepts
|
|
in the opaque object pointed to by
|
|
.Fa flagp .
|
|
Similarly,
|
|
.Fn fesetexceptflag
|
|
changes the specified exception flags to reflect the state stored in
|
|
the object pointed to by
|
|
.Fa flagp .
|
|
Note that the flags restored with
|
|
.Fn fesetexceptflag
|
|
must be a (not necessarily proper) subset of the flags recorded by
|
|
a prior call to
|
|
.Fn fegetexceptflag .
|
|
.Pp
|
|
For all of these functions, the possible types of exceptions
|
|
include those described in
|
|
.Xr fenv 3 .
|
|
Some architectures may define other types of floating-point exceptions.
|
|
.Sh IMPLEMENTATION NOTES
|
|
On some architectures, raising an overflow or underflow exception
|
|
also causes an inexact exception to be raised.
|
|
In these cases, the overflow or underflow will be raised first.
|
|
.Pp
|
|
The
|
|
.Fn fegetexceptflag
|
|
and
|
|
.Fn fesetexceptflag
|
|
routines are preferred to
|
|
.Fn fetestexcept
|
|
and
|
|
.Fn feraiseexcept ,
|
|
respectively, for saving and restoring exception flags.
|
|
The latter do not re-raise exceptions and may preserve
|
|
architecture-specific information such as addresses where
|
|
exceptions occurred.
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn feclearexcept ,
|
|
.Fn fegetexceptflag ,
|
|
.Fn feraiseexcept ,
|
|
and
|
|
.Fn fesetexceptflag
|
|
functions return 0 upon success, and non-zero otherwise.
|
|
The
|
|
.Fn fetestexcept
|
|
function returns the bitwise OR of the values of the current exception
|
|
flags that were requested.
|
|
.Sh SEE ALSO
|
|
.Xr sigaction 2 ,
|
|
.Xr feholdexcept 3 ,
|
|
.Xr fenv 3 ,
|
|
.Xr feupdateenv 3 ,
|
|
.Xr fpgetsticky 3 ,
|
|
.Xr fpresetsticky 3
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn feclearexcept ,
|
|
.Fn fegetexceptflag ,
|
|
.Fn feraiseexcept ,
|
|
.Fn fesetexceptflag ,
|
|
and
|
|
.Fn fetestexcept
|
|
routines conform to
|
|
.St -isoC-99 .
|
|
.Sh HISTORY
|
|
These functions first appeared in
|
|
.Fx 5.3 .
|