From -2907997534295386979 X-Google-Thread: f78e5,51456c3eb8f9490e X-Google-Attributes: gidf78e5,public X-Google-Language: ENGLISH,ASCII Path: g2news2.google.com!news4.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local02.nntp.dca.giganews.com!nntp.speakeasy.net!news.speakeasy.net.POSTED!not-for-mail NNTP-Posting-Date: Mon, 28 Aug 2006 10:20:05 -0500 Return-Path: X-Authentication-Warning: mulga.csse.unimelb.edu.au: fjh set sender to devnull@stump.algebra.com using -f X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-Original-To: std-c++@mailman.ucar.edu Delivered-To: std-c++@mailman.ucar.edu From: "Matthias Hofmann" Newsgroups: comp.std.c++ Subject: Re: Copy Constructor Confusion! Message-ID: <4lg2ecF1o2flU1@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> <4lb16sF130luU1@individual.net> X-Orig-X-Trace: individual.net 2Qdft5KvG2HxSfN4ELFj5wxI0zn16OBS+ZZjkFUz4bSfCaYWoe X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-RFC2646: Format=Flowed; Response X-Originating-IP: 130.133.1.2 X-Virus-Scanned: amavisd-new at ucar.edu X-Virus-Scanned: amavisd-new at csse.unimelb.edu.au Approved: Fergus Henderson , moderator of comp.std.c++ X-Virus-Scanned: amavisd-new at csse.unimelb.edu.au Date: Mon, 28 Aug 2006 10:18:27 CST Lines: 71 NNTP-Posting-Host: 65.182.171.162 X-Trace: sv3-EPygvdGPf92/gOzRWbc/f9UY6Kh0LmxUaJJMpobpdWKhhJv+70nT2XBsT/p/bb+98rpc4xC0PbFQzgu!Fc/Fr6/oa/H3YPjc1t4w49s7yqZUXB6hvFe5kXdOtJA9tpsa9EUJeZPDoxpxxc5iBxps3kPtXmr/!nRXhvEZaBao= X-Complaints-To: abuse@speakeasy.net X-DMCA-Complaints-To: abuse@speakeasy.net 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: 1.3.32 Xref: g2news2.google.com comp.std.c++:3562 ""Martin Vejn�r"" schrieb im Newsbeitrag news:ecrei5$1lo1$1@ns.felk.cvut.cz... > Matthias Hofmann wrote: >> schrieb im Newsbeitrag >> news:1156523477.644185.312570@i42g2000cwa.googlegroups.com... >> [...regarding aggregate initialization...] >> >> The argument is that in the expression >> >> T arr[1] = {}; >> >> there are fewer initializers in the list than there are members in the >> aggregate. Therefore, each member not explicitly initialized shall be >> default-initialized. And default initialization is not copy >> initialization. >> >> What we are discussing here is whether in >> >> T arr[1] = {}; >> >> the object is copy initialized with a temporary that is in turn default >> initialized, such as in >> >> T arr[1] = { T() }; >> >> or whether there is no temporary created, and the object that is default >> initialized is 'arr[0]' rather than a temporary. >> >> If we read 8.5.1/7 again, it says that "EACH MEMBER NOT EXPLICITLY >> INITIALIZED shall be default-initialized". Now which is the member not >> explicitly initialized? 'arr[0]' or the temporary (which I doubt exists >> at all)? > > Is that written in the '03 standard? No, its in the 98 standard. I do not have a copy of the 03 draft. > The newest public draft says [8.5.1/7]: "If there are fewer initializers > in the list than there are members in the aggregate, then each memeber not > explicitly initialized shall be _value-initialized_ (8.5)". I don't know what value-initialized means - does it involve copy construction? > Also, it never uses the term "member of an initializer-list" (that would > be an "initializer"). It is a member of the aggregate that gets > value-initialized, and so the copy constructor is unnessesary. > > Comeau compiles the following code without errors (as it should). > [snipping code] That's my point. The way I understand things, neither the new nor the old standard requires an accessible copy constructor in an expression such as T arr[1] = {}; -- 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 ]