Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: Mikko Newsgroups: comp.theory Subject: Re: Why I need to cross-post to comp.lang.c Date: Sat, 10 May 2025 10:15:04 +0300 Organization: - Lines: 59 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sat, 10 May 2025 09:15:04 +0200 (CEST) Injection-Info: dont-email.me; posting-host="01d78fa0bad8ff028db621577263d594"; logging-data="3592293"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/AkqvqmuZeVUxdnW47UF72" User-Agent: Unison/2.2 Cancel-Lock: sha1:Q1HgLwlYyLpA55uiAak0eThRIZc= On 2025-05-09 03:01:40 +0000, olcott said: > On 5/8/2025 9:23 PM, Keith Thompson wrote: >> Richard Damon writes: >>> On 5/8/25 7:53 PM, olcott wrote: >> [...] >>>> void DDD() >>>> { >>>>   HHH(DDD); >>>>   return; >>>> } >>>> We don't need to look at any of my code for me >>>> to totally prove my point. For example when >>>> the above DDD is correctly simulated by HHH >>>> this simulated DDD cannot possibly reach its own >>>> "return" instruction. >>> >>> And thus not correctly simulatd. >>> >>> Sorry, there is no "OS Exemption" to correct simulaiton;. >> >> Perhaps I've missed something. I don't see anything in the above that >> implies that HHH does not correctly simulate DDD. Richard, you've read >> far more of olcott's posts than I have, so perhaps you can clarify. >> >> If we assume that HHH correctly simulates DDD, then the above code is >> equivalent to: >> >> void DDD() >> { >> DDD(); >> return; >> } >> >> which is a trivial case of infinite recursion. As far as I can tell, >> assuming that DDD() is actually called at some point, neither the >> outer execution of DDD nor the nested (simulated) execution of DDD >> can reach the return statement. Infinite recursion might either >> cause a stack overflow and a probable program crash, or an unending >> loop if the compiler implements tail call optimization. >> >> I see no contradiction, just an uninteresting case of infinite >> recursion, something that's well understood by anyone with a >> reasonable level of programming experience. (And it has nothing to >> do with the halting problem as far as I can tell, though of course >> olcott has discussed the halting problem elsewhere.) >> >> Richard, what am I missing? >> > ***** > Now you are seeing what I was talking about. > Now you are seeing why I needed to cross post > to comp.lang.c What were you told in comp.lang.c that you were not told in comp.theory? -- Mikko