From -4796970556166950366 X-Google-Thread: f78e5,174aa7b34b06a51 X-Google-Attributes: gidf78e5,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news3.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local01.nntp.dca.giganews.com!nntp.speakeasy.net!news.speakeasy.net.POSTED!not-for-mail NNTP-Posting-Date: Tue, 29 Nov 2005 21:40:14 -0600 Return-Path: X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) Delivered-To: std-c++@ucar.edu From: "Sandor Hojtsy" Newsgroups: comp.std.c++ Subject: Re: Is this really unspecified behavior? Organization: http://groups.google.com Message-ID: <1133276211.452281.106150@f14g2000cwb.googlegroups.com> References: <1132629737.664847.151630@o13g2000cwo.googlegroups.com> <1132722639.345095.296070@f14g2000cwb.googlegroups.com> <200511231401.jANE1BuC092897@horus.isnic.is> <37hco1hvfg2s43q2dv3003her7im99airg@4ax.com> <1twif.776$iZ3.758@trndny03> <1133189252.960738.262510@g44g2000cwa.googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Complaints-To: groups-abuse@google.com User-Agent: G2/0.2 X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.12) Gecko/20050915 Firefox/1.0.7,gzip(gfe),gzip(gfe) X-HTTP-Via: 1.1 esprx01 (NetCache NetApp/5.6.2R1) Complaints-To: groups-abuse@google.com Injection-Info: f14g2000cwb.googlegroups.com; posting-host=192.100.124.218; posting-account=DX672Q0AAAC663CjjQDK-b4rLiwACZK0 X-Virus-Scanned: amavisd-new at ucar.edu X-Virus-Scanned: amavisd-new at cs.mu.OZ.AU Approved: Fergus Henderson , moderator of comp.std.c++ X-Virus-Scanned: amavisd-new at cs.mu.OZ.AU Date: Tue, 29 Nov 2005 21:30:55 CST Lines: 26 NNTP-Posting-Host: 65.182.171.162 X-Trace: sv3-e22zDkjLnIY2DH5Ep5dfe1w3EzvEquVlazbCZfdAECYNA4PDTsWRZYXWbkVum9dZLUY6xG7Qxazkd2Q!K+SqDu/A8LCPVRGXMl0Vszcl7i6uJLFo7hjiHlG5uWnMBeoI0PZIYdH2c7ss16egBfhhT4qGHU0I!s5DI/LvWq8XMK8ScSuBvI/2ifxVfQwUuUw9cNW5ONkk= 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: g2news1.google.com comp.std.c++:2629 You keep quoting the standard: i = v[i++]; // the behavior is unspecified i = 7, i++, i++; // i becomes 9 i = ++i + 1; // the behavior is unspecified i = i + 1; // the value of i is incremented Note that this contains an identified defect, it should correctly read: i = v[i++]; // the behavior is undefined i = 7, i++, i++; // i becomes 9 i = ++i + 1; // the behavior is undefined i = i + 1; // the value of i is incremented See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#351 I have a question: are these expressions undefined, or well-formed? i = i = 1; i = ++i; a = (i = 1) + (i = 1); If I take the standard word by word, they do not modify the value of i twice in an expression, because one of the assignments is not modification - just reassigning the existing value. --- [ 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 ]