Re: Can D correctly simulated by H reach its own line 06 and halt?

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.