From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.5-pre1 (2020-06-20) on ip-172-31-74-118.ec2.internal X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=BAYES_00,FROM_ADDR_WS autolearn=no autolearn_force=no version=3.4.5-pre1 Date: 21 Sep 92 04:08:37 GMT From: cis.ohio-state.edu!news.sei.cmu.edu!lph@ucbvax.Berkeley.EDU (Larry Howar d) Subject: Re: Using Global Variables Message-ID: <1992Sep21.040837.10149@sei.cmu.edu> List-Id: Procedural data interfaces show up in many object-oriented designs as services which objects provide for accessing their instance variables. Compilers vary in their abilities to inline and optimize such interfaces. Shared data (as variable objects declared in library-level Ada packages) can be a more efficient alternative to procedurally accessed data, especially when nothing is really being hidden behind the procedural facade. We have been involved in the design of several large, real-time Ada applications (flight simulators) which have used shared memory extensively. I'm happy to report that the bogeyman has not come and carted us off. These applications have realized their engineering goals of modifiability and ease of integration -- as well as efficiency. They are among the largest real-time Ada applications we're aware of. I personally suggest being wary of anyone wishing to raise the use of shared variables to the status of mortal sin. Larry Howard (lph@sei.cmu.edu) | Software Engineering Institute, Carnegie Mellon Univ. | Vera pro gratiis. Pittsburgh, PA 15213-3890 (412) 268-6397/5857 (fax) |