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: 109fba,b87849933931bc93 X-Google-Attributes: gid109fba,public X-Google-Thread: fac41,b87849933931bc93 X-Google-Attributes: gidfac41,public X-Google-Thread: f43e6,b87849933931bc93 X-Google-Attributes: gidf43e6,public X-Google-Thread: 103376,b87849933931bc93 X-Google-Attributes: gid103376,public X-Google-Thread: 1108a1,b87849933931bc93 X-Google-Attributes: gid1108a1,public X-Google-Thread: 114809,b87849933931bc93 X-Google-Attributes: gid114809,public From: kst@aonix.com (Keith Thompson) Subject: Re: OO, C++, and something much better! Date: 1997/01/17 Message-ID: #1/1 X-Deja-AN: 210627548 sender: news@thomsoft.com (USENET News Admin @flash) x-nntp-posting-host: pulsar references: <32DA822A.2FD8@lmtas.lmco.com> <32DCFB78.605A@lmtas.lmco.com> organization: Aonix, San Diego, CA, USA newsgroups: comp.lang.c++,comp.lang.smalltalk,comp.lang.eiffel,comp.lang.ada,comp.object,comp.software-eng originator: kst@pulsar Date: 1997-01-17T00:00:00+00:00 List-Id: In <32DCFB78.605A@lmtas.lmco.com> Ken Garlington writes: [...] > However, via access values, an unchecked conversion could still be used > without creating a copy, so the comment is still valid: using address > specs to create an overlay should not be significantly less/more safe > than unchecked_conversion, at least not for the reason originally > given... Personally, I'd still be more comfortable using Unchecked_Conversion rather than overlays. Part of this is a remnant of Ada-83-think; Ada 83 specifically stated that overlays are erroneous. Also, it's not necessarily guaranteed that updating one of the overlaid objects will update the other; one of the objects may be cached in a register when the other is updated. I believe that applying pragma Volatile to one or both objects will solve this problem (though there may still be some problems I'm missing). -- Keith Thompson (The_Other_Keith) kst@aonix.com <*> TeleSo^H^H^H^H^H^H Alsy^H^H^H^H Thomson Softw^H^H^H^H^H^H^H^H^H^H^H^H^H Aonix 10251 Vista Sorrento Parkway, Suite 300, San Diego, CA, USA, 92121-2706 "SPOON!" -- The Tick