From -6481344554151692524 X-Google-Language: ENGLISH,ASCII X-Google-Thread: f78e5,307cbe6f0ea2ccd3 X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2003-06-09 16:05:52 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!colt.net!kibo.news.demon.net!mutlu.news.demon.net!demon!mail2news.demon.co.uk!devnull From: andreytarasevich@hotmail.com (Andrey Tarasevich) Newsgroups: comp.std.c++ Subject: Re: Recommendation to the Standards Committee Date: Mon, 9 Jun 2003 23:05:51 +0000 (UTC) Organization: Posted via Supernews, http://www.supernews.com Lines: 52 Approved: fjh@cs.mu.oz.au (Fergus Henderson , moderator of comp.std.c++) Message-ID: <3EE50908.9060202@hotmail.com> References: <_ULEa.10852$KF1.271850@amstwist00> Mime-Version: 1.0 Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: quoted-printable X-Trace: mail2news.demon.co.uk 1055199951 18418 10.0.0.1 (9 Jun 2003 23:05:51 GMT) X-Complaints-To: abuse@demon.net NNTP-Posting-Date: Mon, 9 Jun 2003 23:05:51 +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 19PVi2-0004mv-00 for mail2news@news.news.demon.net; Mon, 09 Jun 2003 23:05:50 +0000 X-Received: by mulga.cs.mu.OZ.AU id JAA06163; Tue, 10 Jun 2003 09:05:47 +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-User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 X-Accept-Language: en-us, en X-Spam-Status: No, hits=-8.1 required=5.0 tests=FORGED_HOTMAIL_RCVD,NOSPAM_INC,QUOTED_EMAIL_TEXT, REFERENCES,SATISFACTION,SIGNATURE_SHORT_DENSE, SPAM_PHRASE_00_01,USER_AGENT,USER_AGENT_MOZILLA_UA, X_ACCEPT_LANG version=2.41 X-MIME-Autoconverted: from 8bit to quoted-printable by mulga.cs.mu.OZ.AU id JAA06163 Xref: archiver1.google.com comp.std.c++:19672 Terje Sletteb=F8 wrote: > ""Brian Plummer"" wrote in message > news:ohQDa.44053$4_1.12732776@twister.nyc.rr.com... >> ... >> Well, almost all of the code I write is portable to a large number of >> Hardware/OS/Compiler combinations and I (try to) employ a technique to >> reduce compile times discussed by Lakos on pages 82-88 of "Large Scale > C++ >> Software Design" which advocates protecting every #include file > directive >> with a redundant check for previous inclusion of said header in the >> translation unit. An example could be: >> >> #ifndef __IOSTREAM__ >> #include >> #endif > ... > 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. >=20 > The thread is here > (http://www.google.com/groups?selm=3DXns9343937778AB1conley141osuedu%40= 65. > 24.2.11). > ... Yeah, but it looks like the main point of the method Brian is using is th= at the guarding '#ifndef'/'#endif' is placed _outside_ the header file. In t= his case the preprocessor doesn't even have to search for already included files, open them or try parsing them. The '#once' solution doesn't help i= n this case, since '#once' directive is supposed to be specified _inside_ header files. From this respect '#once' is not much different from the standard "internal '#ifndef'/'#define'/'#endif' approach". But it looks like Brian is not satisfied with the latter. Under this circumstances, I don't think he will be satisfied with any other "internal" solution. --=20 Best regards, Andrey Tarasevich Brainbench C and C++ Programming MVP --- [ 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 ]