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: 103376,2203a21a136b39cc X-Google-Attributes: gid103376,public From: mheaney@ni.net (Matthew Heaney) Subject: Re: Fortran's Equivalence Date: 1997/03/29 Message-ID: #1/1 X-Deja-AN: 229329067 References: <333840D1.7B12@cae.ca> Organization: Estormza Software Newsgroups: comp.lang.ada Date: 1997-03-29T00:00:00+00:00 List-Id: In article , dewar@merv.cs.nyu.edu (Robert Dewar) wrote: >Vigar says > ><< >I have a BIT_PATTERN : System.Unsigned_32. The first 4 bits represent >an integer A, the next 17 represent another record B, the last eleven >represent an integer C. Ada gives something beautiful, in the "use at" >clause, which lets me define a record to superimpose onto the bit >pattern. The big problem with this approach is that it isn't >guaranteed by the LRM, and I need my application to be portable to >other Ada implementations. The Ada Quality and Style Guide, Clause >5.9.4, also tells us that we should not use the "use at" clause to do >such things. I am using the GNAT compiler, 3.07 on the SGI. The final >system will be delivered for a VAX.>> > >The statement in the AQ&S is a holdover from Ada 83 days, and I see no >justification for it. If "use at" does what you want, use it! This is bad advice Robert. The use of Unchecked_Conversion is clearly what is required. -------------------------------------------------------------------- Matthew Heaney Software Development Consultant (818) 985-1271