Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.lang.c > #151301
| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: C String terminator |
| Date | 2020-04-12 21:34 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <87zhbgl9yd.fsf@bsb.me.uk> (permalink) |
| References | (14 earlier) <4b9b90a0-0393-41de-8857-1f8e379e4d79@googlegroups.com> <cc8db103-9023-4756-b19d-158077333c30@googlegroups.com> <2IokG.1296436$ek.27835@fx48.iad> <87h7xpn44g.fsf@bsb.me.uk> <c6ecfa15-23a6-419a-8bbc-e5f9175373b4@googlegroups.com> |
Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:
> On Saturday, 11 April 2020 21:45:30 UTC+1, Ben Bacarisse wrote:
>> Richard Damon <Richard@Damon-Family.org> writes:
>>
>> > On 4/10/20 2:38 PM, Malcolm McLean wrote:
>> >> On Friday, 10 April 2020 15:13:20 UTC+1, 嘱 Tiib wrote:
>> >>>
>> >>> I was asking because you were seemingly claiming that when
>> >>> some used bits are originating from memory mapped input and/or
>> >>> some altered bits go into memory mapped output then it somehow
>> >>> does not matter because the code is likely platform specific.
>> >>> However purity and portability seem to be orthogonal properties
>> >>> of code and correlation seems incidental.
>> >>>
>> >> Pure functions can always be written portably.
>> >
>> > Disagree here. The ONLY way you can make such a claim is to restrict
>> > your machine definition to something that isn't efficient. Either you
>> > need to define that all math is to be done in infinite precision
>> > arithmetic (which is inefficient on most machines), has a language
>> > defined precision (sort of like what Java does so that it is inefficient
>> > on any machine that doesn't well match the language specification) or
>> > you get non-portable answers. C was designed for efficiency over
>> > portability, which is one reason it did succeed in its designed market.
>>
>> I was debating whether to make this point as well. MM is a broad-brush
>> kind of person and I am sure there is some meaning (possibly along the
>> lines you paint here) that is what was really meant. Anyway, for what
>> it's worth, my example was going to be
>>
>> unsigned long long bit_set(void)
>> {
>> return 0x800008000200000020000000800A20AC;
>> }
>>
>> where the author clearly knew that unsigned long long was 128 bits wide.
>>
>> This function can't be written portably (in the usual sense of the word)
>> because not all implementations have an 128-bit unsigned type. The
>> whole program would need to be re-engineered (quite possible including
>> some of the I/O library) to use an invented fake 128-bit integer type.
>> And even that counts as "portable", it's likely that a total re-design
>> of affected parts would be an better option.
>>
>> The fact that this function is pure is, to put is mildly, secondary to
>> the fact that it is very much not portable.
>>
> A function maps bits on entry to bits on exit, and if you want to be
> 100% portable you have to specify it in terms of bits. So yes, you
> need to fake up a 128 bit type if you need 128 bit computations. But
> you can do that.
You appeared to want your odd distinction for "structuring" the code
with, unless I misunderstood, portability in mind. The point of these
examples is that a few Malcolm functions might well be the portability
headaches, and not any of the Malcolm procedures.
<cut>
--
Ben.
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Re: C String terminator Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-02-16 02:25 -0800
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-02-16 14:24 -0800
Re: C String terminator Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-02-22 08:13 -0800
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-02-22 09:05 -0800
Re: C String terminator Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-03-27 19:58 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-03-27 23:26 -0700
Re: C String terminator Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-02 09:21 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-02 09:54 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-02 11:17 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-02 13:12 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-02 13:28 -0700
Re: C String terminator Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-02 19:17 -0700
Re: C String terminator David Brown <david.brown@hesbynett.no> - 2020-04-03 09:47 +0200
Re: C String terminator already5chosen@yahoo.com - 2020-04-03 08:03 -0700
Re: C String terminator David Brown <david.brown@hesbynett.no> - 2020-04-03 17:34 +0200
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-03 12:39 -0400
Re: C String terminator Bart <bc@freeuk.com> - 2020-04-03 18:05 +0100
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-03 10:18 -0700
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-03 22:13 +0100
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-03 14:36 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-03 16:18 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-04 01:43 -0700
Re: C String terminator David Brown <david.brown@hesbynett.no> - 2020-04-04 18:23 +0200
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-04 11:18 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-04 13:02 -0700
Re: C String terminator David Brown <david.brown@hesbynett.no> - 2020-04-05 21:54 +0200
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-05 13:59 -0700
Re: C String terminator David Brown <david.brown@hesbynett.no> - 2020-04-06 09:07 +0200
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-06 02:25 -0700
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-06 11:43 +0100
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-06 03:56 -0700
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-06 16:34 +0100
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-06 10:30 -0700
Re: C String terminator richard@cogsci.ed.ac.uk (Richard Tobin) - 2020-04-06 17:50 +0000
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-06 11:31 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-06 12:04 -0700
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-06 21:51 +0100
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-06 14:34 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-06 14:39 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-06 14:52 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-06 15:31 -0700
Re: C String terminator jameskuyper@stellarscience.com - 2020-04-06 16:05 -0700
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-07 03:08 +0100
Re: C String terminator Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2020-04-06 21:12 -0600
Re: C String terminator scott@slp53.sl.home (Scott Lurndal) - 2020-04-07 16:55 +0000
Re: C String terminator Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2020-04-07 11:05 -0600
Re: C String terminator David Brown <david.brown@hesbynett.no> - 2020-04-07 20:39 +0200
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-07 11:48 -0700
Re: C String terminator Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2020-04-07 21:21 -0600
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-07 20:40 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-08 01:41 -0700
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-08 07:40 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-08 08:16 -0700
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-08 09:17 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-08 09:46 -0700
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-08 10:37 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-08 10:48 -0700
Re: C String terminator Richard Damon <Richard@Damon-Family.org> - 2020-04-08 14:07 -0400
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-08 11:29 -0700
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-08 16:46 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-09 01:57 -0700
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-09 08:42 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-09 08:56 -0700
Re: C String terminator Richard Damon <Richard@Damon-Family.org> - 2020-04-09 12:42 -0400
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-09 10:12 -0700
Re: C String terminator Richard Damon <Richard@Damon-Family.org> - 2020-04-09 15:51 -0400
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-09 13:02 -0700
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-09 13:06 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-09 14:49 -0700
Re: C String terminator Richard Damon <Richard@Damon-Family.org> - 2020-04-09 19:05 -0400
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-10 02:25 -0700
Re: C String terminator Öö Tiib <ootiib@hot.ee> - 2020-04-10 04:38 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-10 05:21 -0700
Re: C String terminator Öö Tiib <ootiib@hot.ee> - 2020-04-10 07:13 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-10 11:38 -0700
Re: C String terminator Ike Naar <ike@sdf.lonestar.org> - 2020-04-11 17:38 +0000
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-11 15:04 -0700
Re: C String terminator Richard Damon <Richard@Damon-Family.org> - 2020-04-11 15:16 -0400
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-11 21:45 +0100
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-12 04:39 -0700
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-12 21:34 +0100
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-12 14:38 -0700
Re: C String terminator Richard Damon <Richard@Damon-Family.org> - 2020-04-13 11:13 -0400
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-13 08:24 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-11 15:08 -0700
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-09 09:53 -0700
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-07 14:35 -0400
Re: C String terminator Öö Tiib <ootiib@hot.ee> - 2020-04-06 21:04 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-07 01:16 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-07 02:08 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-07 02:19 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-07 08:42 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-07 10:39 -0700
Re: C String terminator scott@slp53.sl.home (Scott Lurndal) - 2020-04-07 17:45 +0000
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-07 14:40 -0400
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-07 11:03 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-07 11:14 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-07 12:19 -0700
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-07 12:02 +0100
Re: C String terminator Öö Tiib <ootiib@hot.ee> - 2020-04-07 06:27 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-07 07:44 -0700
Re: C String terminator Öö Tiib <ootiib@hot.ee> - 2020-04-07 08:30 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-07 00:27 -0700
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-07 12:50 +0100
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-07 05:25 -0700
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-07 23:52 +0100
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-08 03:15 -0700
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-08 21:28 +0100
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-08 15:40 -0700
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-09 00:31 +0100
Re: C String terminator Ike Naar <ike@sdf.lonestar.org> - 2020-04-07 21:40 +0000
Re: C String terminator luser droog <luser.droog@gmail.com> - 2020-04-06 09:41 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-06 12:46 -0700
Re: C String terminator Guillaume <message@bottle.org> - 2020-04-07 17:17 +0200
Re: C String terminator Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-09 07:23 -0700
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-04 22:32 +0100
Re: C String terminator David Brown <david.brown@hesbynett.no> - 2020-04-03 21:59 +0200
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-03 23:48 -0400
Jared Kushner would be proud... (Was: C String terminator) gazelle@shell.xmission.com (Kenny McCormack) - 2020-04-04 09:00 +0000
Re: Jared Kushner would be proud... (Was: C String terminator) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-04 02:45 -0700
Re: Jared Kushner would be proud... (Was: C String terminator) Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-04-04 10:24 +0000
Re: Jared Kushner would be proud... (Was: C String terminator) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-04 03:55 -0700
Re: Jared Kushner would be proud... Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-04 13:27 -0700
Re: Jared Kushner would be proud... Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-04 13:52 -0700
Re: Jared Kushner would be proud... Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-04 14:12 -0700
Re: Jared Kushner would be proud... Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-04 15:12 -0700
Re: Jared Kushner would be proud... Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-04 15:03 -0700
Re: Jared Kushner would be proud... Richard Damon <Richard@Damon-Family.org> - 2020-04-04 18:46 -0400
Re: Jared Kushner would be proud... Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-05 01:53 -0700
Re: Jared Kushner would be proud... Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-05 02:33 -0700
Re: Jared Kushner would be proud... Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-05 06:43 -0700
Re: Jared Kushner would be proud... (Was: C String terminator) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-04 19:48 -0700
Re: Jared Kushner would be proud... (Was: C String terminator) James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-04 06:37 -0700
Re: C String terminator David Brown <david.brown@hesbynett.no> - 2020-04-04 18:36 +0200
Re: C String terminator dave_thompson_2@comcast.net - 2020-05-02 15:13 -0400
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-03 09:41 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-03 10:33 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-03 11:14 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-03 11:34 -0700
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-03 14:48 -0400
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-03 12:10 -0700
Re: C String terminator Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-03 13:24 -0700
Re: C String terminator James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-03 23:59 -0400
Re: C String terminator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-04-03 22:05 +0100
Re: C String terminator Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-04 20:34 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-05 02:05 -0700
Re: C String terminator Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-09 07:35 -0700
Re: C String terminator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-04-09 07:38 -0700
csiph-web