RE: libstdc++/10093: Regression: Setting failbit in exceptions doesn't work

["Pétur Runólfsson" <peturr02@ru.is>]

The following reply was made to PR libstdc++/10093; it has been noted by GNATS.

From: =?iso-8859-1?Q?P=E9tur_Run=F3lfsson?= <peturr02@ru.is>
To: <jlquinn@optonline.net>,
	"Martin Sebor" <sebor@roguewave.com>
Cc: <gcc-gnats@gcc.gnu.org>,
	<libstdc++@gcc.gnu.org>
Subject: RE: libstdc++/10093: Regression: Setting failbit in exceptions doesn't work
Date: Mon, 24 Mar 2003 18:21:12 -0000

 I wrote:
 > I agree, however I also think that exceptions() should be consistent
 > with itself, that is, setting exceptions(foobit) should simply mean
 > that whenever foobit is set in rdstate(), an exception is thrown.
 > In the current implementation (and to some extent, the standard)
 > the effect of exceptions(foobit) differs between the various I/O
 > functions and depends on the value of foobit.
 
 Just to clarify:
 
 What I think that ios::exceptions() means (and what appears to have
 been the intent, judging by some old USENET posts) is that this
 should always work:
 
 istream is(...);
 is.exceptions(...);
 ...
 
 try
 {
   is >> x;
   assert((is.exceptions() & is.rdstate()) =3D=3D 0);
 }
 catch (...)
 {
   assert((is.exceptions() & is.rdstate()) !=3D 0);
 }
 
 Likewise for ostream and for unformatted I/O functions. Also, the
 value of is.rdstate() at the end of this code should not depend on
 the value of is.exceptions().
 
 Regards,
 Petur