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From: olcott <polcott333@gmail.com>
Newsgroups: comp.lang.c,comp.lang.c++
Subject: Re: Can D correctly simulated by H reach its own line 06 and halt?
Date: Tue, 21 May 2024 23:03:13 -0500
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On 5/21/2024 9:22 PM, olcott wrote:
> On 5/21/2024 8:31 PM, Sam wrote:
>> olcott writes:
>>
>>> I learned C when K & R was the standard.
>>> I met Bjarne Stroustrup are our local university when he
>>> was promoting his new language. I have been a professional
>>> programmer since 1984, and a professional C++ software
>>> engineer since Y2K.
>>
>> And I have been Lord High Posterchild Of The Known Universe, since 
>> birth. So what?
>>
>>>
>>> I know that my C function template will not execute.
>>
>> Not only that, there is no such thing as "C function template" in the 
>> first place. Templates are a C++ thing. There are not templates in C.
>>
>>> I can't provide the details of this because this template refers to
>>> an infinite set of H/D pairs where H is only required to correctly
>>> simulate N steps of D using an x86 emulator. H must be a pure function.
>>
>> Unfortunately, all our psychics are out to lunch and there's noone in 
>> the office who knows how to operate the magical mind ray-beam machine 
>> that's needed in order to extract all the relevant details from your 
>> head. You'll need to patiently wait until the lunch break is over.
>>
>> We apologize for the inconvenience.
>>
> 
> typedef int (*ptr)();  // ptr is pointer to int function in C
> 00       int H(ptr p, ptr i);
> 01       int D(ptr p)
> 02       {
> 03         int Halt_Status = H(p, p);
> 04         if (Halt_Status)
> 05           HERE: goto HERE;
> 06         return Halt_Status;
> 07       }
> 08
> 09       int main()
> 10       {
> 11         H(D,D);
> 12         return 0;
> 13       }
> 
> It is trivial to see that for every H/D pair of the infinite
> set of H/D pairs that match the above template that
> 
> D correctly correctly simulated by H cannot possibly reach
> its own final state at line 06 and halt because D correctly
> simulated by H remains stuck in recursive simulation.
> 
> This provides the basis for simulating termination analyzer H to
> correctly determine that the halting problem's counter-example
> input D cannot possibly halt.
> 
test
-- 
Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius
hits a target no one else can see." Arthur Schopenhauer