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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,3498dd887729ed19 X-Google-Attributes: gid103376,public From: lars.farm@ite.mh.se (Lars Farm) Subject: Re: Garbage Collection in Ada Date: 1996/10/19 Message-ID: <199610191920401982154@dialup119-3-12.swipnet.se>#1/1 X-Deja-AN: 190647850 references: <01bbb910$f1e73f60$829d6482@joy.ericsson.se> <199610132138291604607@dialup101-6-14.swipnet.se> <19961014235451303023@dialup118-1-7.swipnet.se> <19961016113936528855@dialup120-4-1.swipnet.se> organization: pv nntp-posting-user: s-49817 newsgroups: comp.lang.ada Date: 1996-10-19T00:00:00+00:00 List-Id: Robert Dewar wrote: > it is interesting to note that the mixture of > two such fiddles can sometimes go astray (as is the case with conservative > GC, and manual virtual origin mucking) If you were someone other than Prof. Dewar I'd be tempted to say: "No, you are confused " ;-) User code is not the same thing as the runtime system provided by the implementation. The GC should be provided by the impementation. The language specs imposes no restrictions on the language the runtime system is written in. The runtime system is there in part to encapsulate unportable tricks and hide them from the user. The restrictions imposed by a language spec concerns user code only. Consequently manual virtual origin at the user level is definitly not valid C++. Such code is broken. No matter how popular. Even if it by accident happens to work with this or that compiler on some systems. A conservative collector provided by the implementation as part of the runtime system does not break the rules even if it was written in something that looked like C or C++. It could be written in any language. Including an unportable C-like language only available to the compiler implementors. I assume (but do not know) that the Ada runtime system would be very hard to implement fully in entirely conforming Ada too. -- Lars Farm, lars.farm@ite.mh.se