From 8905305610356699342 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: fc772,cda54862ecb4a41f X-Google-Attributes: gidfc772,public X-Google-Thread: f78e5,cda54862ecb4a41f X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2001-08-27 08:02:17 PST Path: archiver1.google.com!newsfeed.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!feed.news.qwest.net!namche.sun.com!news2me.EBay.Sun.COM!engnews1.eng.sun.com!taumet!clamage From: "James Russell Kuyper Jr." Newsgroups: comp.std.c++,comp.lang.c++.moderated Subject: Re: storage order of inherited classes Date: 27 Aug 2001 14:55:42 GMT Organization: Posted via Supernews, http://www.supernews.com Lines: 41 Approved: stephen.clamage@sun.com (comp.std.c++) Message-ID: <3B88CE59.624F4BDD@wizard.net> References: NNTP-Posting-Host: taumet.eng.sun.com X-NNTP-Posting-Host: netlab.cs.rpi.edu X-Original-Date: Sun, 26 Aug 2001 06:24:25 -0400 X-Submission-Address: c++-submit@netlab.cs.rpi.edu X-Auth: PGPMoose V1.1 PGP comp.lang.c++.moderated iQBVAwUAO4mU+UHMCo9UcraBAQHUigH9FCTy6Ld9OdDfdQBrWdFPm+9/nB3GoldJ Pw+KF2eYoD2EvIVqpDBRvfsxzT9P37Cq0QTX1JoMkTr54b1YgTNYQA== =cFqp X-Approved-For-Group: hsutter@acm.org comp.lang.c++.moderated Content-Length: 1556 X-Status: $$$$ X-UID: 0000000001 Originator: clamage@taumet Xref: archiver1.google.com comp.std.c++:7175 comp.lang.c++.moderated:25424 Fray Bentos wrote: > > Hey peeps. > > Im involved in optimising a few C++ classes that interface with OpenGL > I was wondering if the memory storage order of class members is > standardised ? Yes, but only to a degree: 9.2p12: "Nonstatic data members of a (non-union) class declared without an intervening _access-specifier_ are allocated so that later members have higher addresses within a class object. The order of allocation of nonstatic data members separated by an _access-specifier_ is unspecified (11.1). Implementation alignment requirements might cause two adjacent members not to be allocated immediately after each other; so might requirements for space for managing virtual functions (10.3) and virtual base classes (10.1)." 10.1p3: "The order in which the base class subobjects are allocated in the most derived object (1.8) is unspecified. ..." > Will the array j from the derived class B always be stored before i from the > base class A ? Because of 10.1p3, there's no guarantee about the position of j relative to i. [ Send an empty e-mail to c++-help@netlab.cs.rpi.edu for info ] [ about comp.lang.c++.moderated. First time posters: do this! ] [ 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.research.att.com/~austern/csc/faq.html ] [ Note that the FAQ URL has changed! Please update your bookmarks. ]