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Groups > comp.lang.c > #382175
| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Is C ready to become a safer language? |
| Date | 2024-02-09 10:24 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <8734u2q6k6.fsf@bsb.me.uk> (permalink) |
| References | (3 earlier) <87bk8rgcy0.fsf@nosuchdomain.example.com> <uq2um0$21dgh$1@dont-email.me> <uq4jm5$2h9hc$2@dont-email.me> <uq4l7p$2hik2$1@dont-email.me> <uq4o03$2hive$7@dont-email.me> |
David Brown <david.brown@hesbynett.no> writes: > On 09/02/2024 08:46, Malcolm McLean wrote: >> On 09/02/2024 07:19, David Brown wrote: >>> On 08/02/2024 17:14, Malcolm McLean wrote: >>>> On 08/02/2024 16:04, Keith Thompson wrote: >>> >>>>> In a freestanding implementation, main() *might* be just another >>>>> function. In that case a compiler can't prove that the code will be >>>>> invoked. >>>>> >>>> Well sometimes it can. The boot routine or program entry point is by >>>> defintion always invoked, and you can generally prove that at least >>>> some code is always reached from that. However it is the halting >>>> problem, and you can never prove for all cases, even if the code must >>>> be reached or not reached regardless of runtime inputs. >>>> >>> >>> It is not "the halting problem". What you are trying to say, is that it >>> is undecidable or not a computable problem in the general case. >>> >> The "is this code reached?" problem is the halting problem with the >> trivial and unimportant difference that the code in question does not >> have to be "exit()". > > No, it is not. > > The two problems can be shown to be equivalently "hard" - that is, if you > could find a solution to one, it would let you solve the other. But that > does not make them the same problem. Sure. But it's not the halting problem for another reason as well. In the formal models (that have halting problems and so on), it's "the computation" that is the problem instance. That is, the code and all the data are presented for an answer. A C compiler has to decide on reachability without knowing the input. For example, is this code "undefined": int c, freq[128]; while ((c = getchar()) != EOF) freq[c]++; ? Maybe it was knocked up as a quick way to collect stats on base64 encoded data streams. If so, it's fine (at least in terms of UB). -- Ben.
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Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 01:01 -0300
Re: Is C ready to become a safer language? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-02-08 04:40 +0000
Re: Is C ready to become a safer language? Kaz Kylheku <433-929-6894@kylheku.com> - 2024-02-08 05:00 +0000
Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 09:20 -0300
Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-08 17:02 +0000
Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 14:17 -0300
Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 14:19 -0300
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-08 09:57 -0800
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-08 09:45 -0800
Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 14:56 -0300
Re: Is C ready to become a safer language? Kaz Kylheku <433-929-6894@kylheku.com> - 2024-02-08 04:58 +0000
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-07 21:33 -0800
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-07 20:59 -0800
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-08 09:17 +0100
Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 09:48 -0300
Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-08 14:42 +0000
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-08 16:25 +0100
Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 13:15 -0300
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-08 21:42 +0100
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-08 08:04 -0800
Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-08 16:14 +0000
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-08 08:32 -0800
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 08:19 +0100
Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-09 07:46 +0000
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 09:33 +0100
Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-09 10:03 +0000
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 11:17 +0100
Re: Is C ready to become a safer language? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-02-09 10:24 +0000
Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-09 11:24 +0000
Re: Is C ready to become a safer language? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-02-09 13:28 +0000
Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-09 14:04 +0000
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 15:03 +0100
ustent on that. Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-09 16:01 +0000
Re: ustent on that. David Brown <david.brown@hesbynett.no> - 2024-02-09 18:00 +0100
Re: ustent on that. Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-10 01:20 +0000
Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-09 12:45 +0000
Re: Is C ready to become a safer language? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-02-09 13:01 +0000
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 15:08 +0100
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-09 08:48 -0800
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 08:14 +0100
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-09 08:28 -0800
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 20:15 +0100
Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-02-10 02:28 -0800
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-10 16:15 -0800
Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-02-10 23:22 -0800
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-11 00:12 -0800
Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-02-11 23:48 -0800
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-18 15:28 -0800
Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-23 10:35 -0700
Re: Is C ready to become a safer language? Richard Kettlewell <invalid@invalid.invalid> - 2024-02-08 15:37 +0000
Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 13:25 -0300
Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-08 16:30 +0000
Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-02-09 17:59 -0800
Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-10 20:22 +0000
Re: Is C ready to become a safer language? Richard Harnden <richard.nospam@gmail.invalid> - 2024-02-10 21:30 +0000
Re: Is C ready to become a safer language? Kaz Kylheku <433-929-6894@kylheku.com> - 2024-02-10 21:49 +0000
Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-10 20:44 -0300
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-11 13:06 +0100
Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-11 15:43 -0300
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-11 13:33 -0800
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-12 11:32 +0100
Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-11 00:02 +0000
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-10 17:39 -0800
Re: Is C ready to become a safer language? Kaz Kylheku <433-929-6894@kylheku.com> - 2024-02-11 02:46 +0000
Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-11 12:24 +0000
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-11 15:06 +0100
Re: Is C ready to become a safer language? Kaz Kylheku <433-929-6894@kylheku.com> - 2024-02-11 18:32 +0000
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-11 13:15 +0100
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-10 16:31 -0800
Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-11 15:57 -0300
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-11 13:47 -0800
Re: Is C ready to become a safer language? vallor <vallor@cultnix.org> - 2024-02-11 00:40 +0000
Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-11 01:06 +0000
Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-10 17:51 -0800
Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-11 13:27 +0100
Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-02-10 19:54 -0800
Re: Is C ready to become a safer language? vallor <vallor@cultnix.org> - 2024-02-13 06:22 +0000
Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-11 11:01 +0000
Re: Is C ready to become a safer language? Richard Harnden <richard.nospam@gmail.invalid> - 2024-02-11 11:31 +0000
Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-11 12:38 +0000
Re: Is C ready to become a safer language? Richard Harnden <richard.nospam@gmail.invalid> - 2024-02-11 13:23 +0000
Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-11 14:17 +0000
Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-02-10 22:21 -0800
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