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From: Mikko <mikko.levanto@iki.fi>
Newsgroups: comp.theory
Subject: Re: Why I need to cross-post to comp.lang.c
Date: Sat, 10 May 2025 10:15:04 +0300
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On 2025-05-09 03:01:40 +0000, olcott said:

> On 5/8/2025 9:23 PM, Keith Thompson wrote:
>> Richard Damon <richard@damon-family.org> 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