From 4191515392195799132 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,307cbe6f0ea2ccd3 X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2003-06-10 11:22:56 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed.icl.net!newsfeed.fjserv.net!kibo.news.demon.net!mutlu.news.demon.net!demon!mail2news.demon.co.uk!devnull From: do-not-spam-ben.hutchings@businesswebsoftware.com (Ben Hutchings) Newsgroups: comp.std.c++ Subject: Re: Recommendation to the Standards Committee Date: Tue, 10 Jun 2003 18:22:55 +0000 (UTC) Lines: 33 Approved: fjh@cs.mu.oz.au (Fergus Henderson , moderator of comp.std.c++) Message-ID: References: <_ULEa.10852$KF1.271850@amstwist00> X-Trace: mail2news.demon.co.uk 1055269375 22957 10.0.0.1 (10 Jun 2003 18:22:55 GMT) X-Complaints-To: abuse@demon.net NNTP-Posting-Date: Tue, 10 Jun 2003 18:22:55 +0000 (UTC) X-Received: from mulga.cs.mu.oz.au ([128.250.1.22]) by news.demon.co.uk with esmtp (Exim 4.12) id 19Pnlm-0005y8-00 for mail2news@news.news.demon.net; Tue, 10 Jun 2003 18:22:54 +0000 X-Received: by mulga.cs.mu.OZ.AU id EAA04849; Wed, 11 Jun 2003 04:22:51 +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++@ucar.edu X-Newsgroups: comp.std.c++ X-Reply-To: Ben Hutchings X-Orig-NNTP-Posting-Host: gold.businesswebsoftware.com (195.74.108.82) X-Orig-X-Trace: fu-berlin.de 1055244566 16037077 195.74.108.82 (16 [70929]) X-User-Agent: slrn/0.9.7.4 (Win32) X-Spamscanner: mailbox3.ucsd.edu (v1.2 May 26 2003 01:55:38, -2.0/5.0 2.55) X-MailScanner: PASSED (v1.2.7 33930 h5ABTSQS039185 mailbox3.ucsd.edu) X-Spam-Status: No, hits=-7.2 required=5.0 tests=QUOTED_EMAIL_TEXT,REFERENCES,SPAM_PHRASE_03_05,USER_AGENT version=2.41 Xref: archiver1.google.com comp.std.c++:19675 In article , "Brian Plummer" wrote: >>> A better way might be the "#once" directive, which has been discussed >>> recently, which ensures that the header using it is only included once. >>> This means you have no dependency on the included file, and files >>> including it don't need to be changed. >>> >>> The thread is here >>> (http://www.google.com/groups?selm=Xns9343937778AB1conley141osuedu%4065. >>> 24.2.11). > > > That is definitely an even better idea! Google could not locate the thread > that you referenced in your reply. You need to paste those two lines together. Some news or mail software has word-wrapped that line wrongly. > In general I'd like to see that this topic is at least on the discussion > agenda for the Library Standards Committee. I don't know how to do this, > do you? This was discussed to death only a few months ago in the thread referenced above. It turns out to be impractical to implement #once on many systems as file identities cannot reliably be compared. #ifndef guards can do the job and where file identities can be compared some compilers/preprocessors are smart enough to recognise guarded headers and avoid reading them again. --- [ 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 ]