From -5263461996019747774 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,96a8c01f7043c2d9 X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2002-09-09 12:03:44 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!kibo.news.demon.net!mutlu.news.demon.net!demon!mail2news.demon.co.uk!devnull From: glancaster@ntlworld.com ("Garry Lancaster") Newsgroups: comp.std.c++ Subject: Re: Proposal: exception stack unwinding resumption Date: Mon, 9 Sep 2002 19:03:44 +0000 (UTC) Organization: ntl Cablemodem News Service Lines: 57 Approved: fjh@cs.mu.oz.au (Fergus Henderson , moderator of comp.std.c++) Message-ID: References: <6df0c6a8.0208260746.633710cb@posting.google.com> <6df0c6a8.0209030656.249192ce@posting.google.com> <6df0c6a8.0209051026.5df687db@posting.google.com> X-Trace: mail2news.demon.co.uk 1031598224 1818 10.0.0.1 (9 Sep 2002 19:03:44 GMT) X-Complaints-To: abuse@demon.net NNTP-Posting-Date: Mon, 9 Sep 2002 19:03:44 +0000 (UTC) X-Received: from mulga.cs.mu.oz.au ([128.250.1.22]) by news.demon.co.uk with esmtp (Exim 4.05) id 17oTp0-0000TA-00 for mail2news@news.news.demon.net; Mon, 09 Sep 2002 19:03:42 +0000 X-Received: by mulga.cs.mu.OZ.AU id FAA22632; Tue, 10 Sep 2002 05:03:09 +1000 (EST) X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f X-Path: comp-std-cpp-robomod!not-for-mail X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-Delivered-To: std-c++@ncar.ucar.edu X-Newsgroups: comp.std.c++ X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.00.2615.200 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2615.200 X-NNTP-Posting-Date: Mon, 09 Sep 2002 11:09:10 BST Xref: archiver1.google.com comp.std.c++:13720 Garry Lancaster: > > Good general advice is to do as the standard library > > does and not to throw from a destructor. Clean-up > > which really can fail is done in a non-destructor > > function. Pierre Baillargeon: > I'd agree if RAII had not made me so much more productive. I could > write a long rant detailing my experience, but I'll simply say this: > these posts made me reflect on my usage of RAII and I realized that > for an entire year I completely forgot that there could be bugs in the > base layer of my design because it has been so flawless, thanks to > RAII. Unfortunately, it means my destructors can throw. Aha. This is the root of all the confusion, I think. RAII does not mean destructors must be able to throw. If you are using your throwing destructors with the standard libary or any other template library you really need to address this misconception. See for example this part of the C++ standard: "[lib.res.on.functions] 17.4.3.6 Other functions 1 In certain cases (replacement functions, handler functions, operations on types used to instantiate standard library template components), the C + + Standard Library depends on components supplied by a C + + program. If these components do not meet their requirements, the Standard places no requirements on the implementation. 2 In particular, the effects are undefined in the following cases: .... - if any replacement function or handler function or destructor operation throws an exception, unless specifically allowed in the applicable Required behavior paragraph." If you have a particular cleanup sequence you are having trouble implementing without a no-throw destructor, you could post it here, although the solution will likely be along the lines already discussed. Kind regards Garry Lancaster Codemill Ltd Visit our web site at http://www.codemill.net --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ]