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-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,6bf481efd29cf77b X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2002-06-15 19:32:12 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!sn-xit-03!sn-post-01!supernews.com!corp.supernews.com!not-for-mail From: "Randy Brukardt" Newsgroups: comp.lang.ada Subject: Re: Behavior of Stream Attributes On Access Types. Date: Sat, 15 Jun 2002 21:27:44 -0500 Organization: Posted via Supernews, http://www.supernews.com Message-ID: References: <4519e058.0206110547.526d2369@posting.google.com> X-Newsreader: Microsoft Outlook Express 4.72.3612.1700 X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3719.2500 X-Complaints-To: newsabuse@supernews.com Xref: archiver1.google.com comp.lang.ada:26059 Date: 2002-06-15T21:27:44-05:00 List-Id: Simon Wright wrote in message ... >"Marin David Condic" writes: > >> Nope. Not a "mistake" - except maybe stylistically. I have evolved a >> very specific question here that seems to be getting >> misunderstood. I don't want to know how to override the default >> 'Read and 'Write for an access type. (I know *how* to do that - but >> not necessarily what the "default" behavior is. From other posts, I >> suspect just the pointer value is written.) What I want to know is >> what happens as you go up the food-chain on tagged records once you >> override the default 'Read and 'Write. > >Oh, sorry; I guess what we're all failing to grasp is why you would >want to do that. > >Since the only contribution I would be able to make would be to try it >and see, I'll shut up .. And I answered that question (in terms of the Corrigendum and the original Ada 95 standard) several days ago (Wednesday to be exact). Here it is again if you all missed it: "The Ada 95 standard doesn't address this. The Technical Corrigendum does, and requires that the default implementation is calls the parent type's 'Read and 'Write. So you are not required to override. But be sure that your compiler is implementing the TC (tests for this area have only recently been added to the ACATS, so it is not unlikely that compilers don't follow the TC in this area)." To expand a bit further, the TC requires that the default implementation calls the parent type's 'Read and 'Write, along with the 'Read and 'Writes for any extension components. So you don't have to do anything special, and you should get what you expect. But, again, be sure that your compiler implements the TC before depending on this! (If it doesn't implement the TC, it could do just about anything; the original Ada 95 standard is very confused when it comes to streams and stream attributes). Randy Brukardt.