From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,80bc3e0698be468f X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news1.google.com!news3.google.com!news.glorb.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local01.nntp.dca.giganews.com!nntp.megapath.net!news.megapath.net.POSTED!not-for-mail NNTP-Posting-Date: Fri, 27 Jan 2006 17:19:42 -0600 From: "Randy Brukardt" Newsgroups: comp.lang.ada References: <1138260496.230283.147640@g43g2000cwa.googlegroups.com> <1138283608.433842.76060@z14g2000cwz.googlegroups.com> <43D8E85C.6020805@mailinator.com> <1535741.yb0A0MsH1D@linux1.krischik.com> <43D912A3.2030201@mailinator.com> <43DA0061.1050501@mailinator.com> Subject: Re: Type safety on wikipedia Date: Fri, 27 Jan 2006 17:24:33 -0600 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Message-ID: NNTP-Posting-Host: 64.32.209.38 X-Trace: sv3-59IS3957F3tLCX7BqJXNYPB7cjnTUsxZt0PYk/Dip6meLfWTaNzf1s1Mu3bckUeHj6fJsZsQWzB4Not!uPndVwMB5myK5cTItsRpRKJlcuo4msgUDyB//6q73IpZs28EnKv6x57wEzcBhADPCdSfWkB5vsBr X-Complaints-To: abuse@megapath.net X-DMCA-Complaints-To: abuse@megapath.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.lang.ada:2692 Date: 2006-01-27T17:24:33-06:00 List-Id: "Simon Wright" wrote in message news:m23bj9h35k.fsf@grendel.local... ... > One point I had forgotten is that deallocation of a controlled object > will finalize it -- LRM 13.11.2(9) -- so looking at it through a > dangling pointer will be a Bad Thing even if GC has ensured that the > mamory hasn't been re-used for something else. Which reminds me of a significant issue: Ada 95 doesn't allow early (or late) finalization of limited controlled objects. (Whether it allows early finalization of nonlimited controlled objects is open to debate.) That means that GC cannot collect objects containing limited controlled components "early". But since a program written with GC in mind won't use Unchecked_Deallocation, and the access types will likely be library level, "early" and "anytime before completion of main" are the same. Since I think most objects in a program ought to be controlled, that's a significant problem. We talked about this a few times, but never came near a consensus on how to fix this, so Ada 2005 inherits the issue intact. I suppose if anyone was seriously trying to use GC in their implementation, the priority level would go up... Randy.