Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: olcott Newsgroups: comp.theory Subject: Re: Overcoming the proof of undecidability of the Halting Problem by a simple example in C Date: Sun, 18 May 2025 20:24:06 -0500 Organization: A noiseless patient Spider Lines: 68 Message-ID: <100e17m$194d7$1@dont-email.me> References: <1005jsk$3akrk$1@dont-email.me> <1005u6v$3cpt2$1@dont-email.me> <1005v0p$3b07v$1@dont-email.me> <10063u0$3dmiv$1@dont-email.me> <1006on8$3l9t7$1@dont-email.me> <1007kgq$3qb7l$9@dont-email.me> <1009lm9$b15q$1@dont-email.me> <100ceum$uvq0$1@dont-email.me> <87ecwl1s2p.fsf@bsb.me.uk> <100dscu$18b5s$1@dont-email.me> <87v7pxzbp4.fsf@bsb.me.uk> <100du9m$18m8u$1@dont-email.me> <100dvuj$18b5q$2@dont-email.me> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Mon, 19 May 2025 03:24:07 +0200 (CEST) Injection-Info: dont-email.me; posting-host="54427c6633a8689b841d1d48a1b07f55"; logging-data="1348007"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18NzqANhqa+MorDshU4uZyB" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:I1DwOlllJ/XEdOpYByods5vU7o0= X-Antivirus: Norton (VPS 250518-4, 5/18/2025), Outbound message X-Antivirus-Status: Clean In-Reply-To: <100dvuj$18b5q$2@dont-email.me> Content-Language: en-US On 5/18/2025 8:02 PM, Richard Heathfield wrote: > On 19/05/2025 01:33, olcott wrote: >> On 5/18/2025 7:27 PM, Ben Bacarisse wrote: >>> Richard Heathfield writes: > > [Apologies for not snipping. This one was hard to know how best to edit > down.] > >>> >>>> On 18/05/2025 23:18, Ben Bacarisse wrote: >>>>> Richard Heathfield writes: >>>>> ... >>>>>> If they know C they should know that it's >>>>>>    u32 HHH(void (*P)()), according to Halt7.c. >>>>>> >>>>>> It takes a pointer to a function that accepts no arguments and >>>>>> returns no >>>>>> value. >>>>> Yes, but I am surprised that you are being so modern!!  You used to >>>>> favour C90 and didn't really care for anything more recent. >>>> >>>> I am just as surprised that you missed the distinction I was making, >>>> which >>>> was between these: >>>> >>>> void HHH(void (*f)(void)) >>>> u32 HHH(void (*P)()) >>>> >>>> Empty parentheses had nothing to do with my point. On line 16 we find: >>>> typedef uint32_t u32; >>>> >>>> uint32_t != void. >>> >>> Yes, I got the distinction you were making, but I must have got confused >>> about the referent of "it" in the part I quoted.  I was hoping to add >>> to the discussion despite ignoring your main point.  Sorry. >>> >> >> *Copied from the original post that he responded to* >> >> int DD() >>   { >>    int Halt_Status = HHH(DD); >>    if (Halt_Status) >>      HERE: goto HERE; >>    return Halt_Status; >>   } > > Not so. The post I responded to was Message-ID: <1009lm9$b15q$1@dont- > email.me> > > There was a lot of quoted material, none of which mentioned int DD(), > although it did mention a void DDD(). > > The only original material was: > > +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > No, there are peole who do know C but don't know that HHH is not > void HHH(void (*f)(void)) {} and how therefore cannot tell that > HHH does simulate DDD. > It was stipulated that HHH does simulate DDD. No need to check every little punctuation mark. -- Copyright 2025 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer