From -1160314889317767166 X-Google-Thread: f78e5,51456c3eb8f9490e X-Google-Attributes: gidf78e5,public X-Google-Language: ENGLISH,ASCII Path: g2news2.google.com!news3.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!newsfeed00.sul.t-online.de!t-online.de!tiscali!newsfeed1.ip.tiscali.net!news.tiscali.de!newsfeed.hanau.net!newsfeed.vmunix.org!peer-uk.news.demon.net!kibo.news.demon.net!mutlu.news.demon.net!news.demon.co.uk!demon!stump.algebra.com!devnull From: hofmann@anvil-soft.com ("Matthias Hofmann") Newsgroups: comp.std.c++ Subject: Re: Copy Constructor Confusion! Date: Sat, 26 Aug 2006 20:30:15 GMT Lines: 65 Sender: mail2news@demon.net Approved: fjh@cs.mu.oz.au (Fergus Henderson , moderator of comp.std.c++) Message-ID: <4lb16sF130luU1@individual.net> References: <1155645873.296811.3890@74g2000cwt.googlegroups.com> <4kebv5Fbjid9U3@individual.net> <1155833275.678725.297060@h48g2000cwc.googlegroups.com> <44e73f70$0$10146$9b4e6d93@newsspool2.arcor-online.net> <1156162332.681008.153540@m73g2000cwd.googlegroups.com> <4l60udFecegU1@individual.net> <1156512377.765813.77030@b28g2000cwb.googlegroups.com> <1156523477.644185.312570@i42g2000cwa.googlegroups.com> NNTP-Posting-Host: news.news.demon.net Mime-Version: 1.0 Content-Type: text/plain; charset=unknown-8bit Content-Transfer-Encoding: quoted-printable X-Trace: news.demon.co.uk 1156624219 21182 158.152.254.254 (26 Aug 2006 20:30:19 GMT) X-Complaints-To: abuse@demon.net NNTP-Posting-Date: Sat, 26 Aug 2006 20:30:19 +0000 (UTC) X-Original-To: std-c++@mailman.ucar.edu X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-MIME-Autoconverted: from 8bit to quoted-printable by mulga.csse.unimelb.edu.au id k7QKUGFS021433 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Priority: 3 X-Greylisting: NO DELAY (Relay+Sender autoqualified); processed by UCSD_GL-v2.1 on mailbox7.ucsd.edu; Sat, 26 August 2006 06:38:39 -0700 (PDT) X-Orig-X-Trace: individual.net ThyZXmpAs/160TP/hrRJkwGGzz/9vpbRCk+MR/1eTSjKqKpkR8 X-RFC2646: Format=Flowed; Original X-Virus-Scanned: amavisd-new at csse.unimelb.edu.au X-MSMail-Priority: Normal X-Originating-IP: 130.133.1.2 X-Received: (from fjh@localhost) by mulga.csse.unimelb.edu.au (8.13.6+Sun/8.13.6/Submit) id k7QKUFaS021417; Sun, 27 Aug 2006 06:30:15 +1000 (EST) X-Path: comp-std-cpp-robomod!not-for-mail X-Delivered-To: std-c++@mailman.ucar.edu X-Spamscanner: mailbox7.ucsd.edu (v1.6 Jul 6 2006 16:38:12, -1.4/5.0 3.1.3) X-Authentication-Warning: mulga.csse.unimelb.edu.au: fjh set sender to devnull@stump.algebra.com using -f X-Newsreader: Microsoft Outlook Express 6.00.2900.2180 X-Newsgroups: comp.std.c++ X-MailScanner: PASSED (v1.2.8 75134 k7QDcbGb081427 mailbox7.ucsd.edu) Xref: g2news2.google.com comp.std.c++:3538 schrieb im Newsbeitrag=20 news:1156523477.644185.312570@i42g2000cwa.googlegroups.com... > Frederick Gotham wrote: >> kanze posted: >> >> > According to =A78.5.1/7: "If there are fewer initializers in the >> > list than there are members in the aggregate, then each member >> > not explicitly initialized shall be default-initialized." So >> > T arr[1] =3D {} ; >> > is the equivalent of: >> > T arr[1] =3D { T() } ; >> > which is the equivalent of: >> > T arr =3D T() ; >> >> >> I don't think you're corrected there. Just because something is defaul= t- >> initialised, doesn't mean there's a copy-construction involved. > > That's correct, but it misses the point. Re-read his post. It isn't the > default-initialization that determines this, it's the use of > brace-enclosed initializer list - per 8.5/12, his citation of which > you've cut out of your reply. You need an argument to justify ignoring > 8.5/12. I haven't seen one. The argument is that in the expression T arr[1] =3D {}; there are fewer initializers in the list than there are members in the=20 aggregate. Therefore, each member not explicitly initialized shall be=20 default-initialized. And default initialization is not copy initializatio= n. What we are discussing here is whether in T arr[1] =3D {}; the object is copy initialized with a temporary that is in turn default=20 initialized, such as in T arr[1] =3D { T() }; or whether there is no temporary created, and the object that is default=20 initialized is 'arr[0]' rather than a temporary. If we read 8.5.1/7 again, it says that "EACH MEMBER NOT EXPLICITLY=20 INITIALIZED shall be default-initialized". Now which is the member not=20 explicitly initialized? 'arr[0]' or the temporary (which I doubt exists a= t=20 all)? --=20 Matthias Hofmann Anvil-Soft, CEO http://www.anvil-soft.com - The Creators of Toilet Tycoon http://www.anvil-soft.de - Die Macher des Klomanagers --- [ 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.comeaucomputing.com/csc/faq.html ]