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: 10db24,77f71d0bde4c5bb4 X-Google-Attributes: gid10db24,public X-Google-Thread: 103376,86fd56abf3579c34 X-Google-Attributes: gid103376,public From: gt2782a@prism.gatech.edu (Richard Ladd Kirkham) Subject: Re: What good is halting prob? Date: 1995/04/19 Message-ID: <3n429h$pvu@acmex.gatech.edu>#1/1 X-Deja-AN: 101283255 sender: gt2782a@prism.gatech.edu references: <1995Apr19.204744.21914@wdl.loral.com> organization: Georgia Institute of Technology newsgroups: comp.lang.ada,comp.edu Date: 1995-04-19T00:00:00+00:00 List-Id: In article <1995Apr19.204744.21914@wdl.loral.com> mab@dst17.wdl.loral.com (Mark A Biggar) writes: > >Another example: determining if changing the parameter passing method from >by-refernece to copy-in-copy-out and vis-versa changes the behaviour of >your program is also equivalent to the Halting Problem. The Ada83 LRM >says that such programs are erroneous, but the above result means that >detecting such programs at compile time is not possible in gerneral. > I don't get this. *What* programs is the LRM calling erroneous? Also, aside from a hardware failure or hardware inadequacy, wouldn't two other wise identical programs, one using by-reference and the other copy-in-copy back, behave identically? -- Richard Ladd Kirkham Georgia Institute of Technology, Atlanta Georgia, 30332 uucp: ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!gt2782a Internet: gt2782a@prism.gatech.edu