From -4598832105150658329 X-Google-Thread: 7894ca11fe,82cd3599ce330676 X-Google-Attributes: gid7894ca11fe,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news2.google.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!news.giganews.com.POSTED!not-for-mail NNTP-Posting-Date: Wed, 31 Mar 2010 22:50:01 -0500 Return-Path: To: (Usenet) From: Jonathan de Boyne Pollard Newsgroups: comp.std.c++ Subject: Re: throwing in a noexcept(true) function Organization: Wacks Wicks Works Sender: cppmods@cs.rpi.edu Approved: james.dennett@gmail.com Message-ID: References: <3707c5ae-e25f-4ca2-9195-8b8be17ddec1@b9g2000pri.googlegroups.com> <4BAE1663.1E83B5D3@web.de> <8i12r5hoe7gqsiagpjv12103gtdo0vbh39@4ax.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed X-Original-Date: Tue, 30 Mar 2010 21:41:08 +0100 X-Submission-Address: std-c++@netlab.cs.rpi.edu Date: Wed, 31 Mar 2010 22:49:04 CST Lines: 31 X-Usenet-Provider: http://www.giganews.com X-Trace: sv3-u5F2sXKgX5on87a94FGEM3KkMXwOk0lKrpbhYw4YbqqMvaCZ9p45LFuEH1TpOfb3hQK/5uk4znr2URw!oN5NSuJfemd2gfxm2kVCvDPRzMOAkeZBzAnHqxR4YSqVhpEbeMvJrXRvPWUCfUoOTDfPiqNysW0W!+hJYJjGtN5C+My3fIg== X-Complaints-To: abuse@giganews.com X-DMCA-Notifications: http://www.giganews.com/info/dmca.html X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 Xref: g2news1.google.com comp.std.c++:2350 > > > To summarize, the main two points of view that were expressed were that that trying to propagate an exception out of a noexcept function should result in: > > a) All bets off: Undefined behavior [...] > > b) Termination: [...] > > The committee has currently penciled in (b). > Another choice that was suggested by some members of the BSI C++ Panel is: c) implementation-defined behaviour It's not undefined behaviour, but, equally, it's not as rigid as "the program shall always terminate", either; which would satisfy those who are (I am told) in the "option (b) is premature standardization" camp. > In particular, noexcept enables optimizations not only in the caller but also in the callees, so that the optimizer can assume that functions called in a noexcept function and not wrapped in a try/catch are themselves noexcept without being declared such (e.g., C standard library functions are not so annotated). > That's not the way that other people are seeing this. Indeed, one question that is doing the rounds is whether the two strchr()s in the C++ library should be declared noexcept(true) in the text of the standard. -- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@netlab.cs.rpi.edu] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.comeaucomputing.com/csc/faq.html ]