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| Message-ID | <3gulkd-1ds.ln1@wilbur.25thandClement.com> (permalink) |
|---|---|
| From | <william@wilbur.25thandClement.com> |
| Subject | Re: standard error codes |
| Newsgroups | comp.lang.c |
| References | (9 earlier) <lneg09pazg.fsf@kst-u.example.com> <o566pk$nok$1@dont-email.me> <87o9zdtgzo.fsf@gmail.com> <o57o66$urn$1@dont-email.me> <lnwpe0nq6n.fsf@kst-u.example.com> |
| Date | 2017-01-12 19:34 -0800 |
Keith Thompson <kst-u@mib.org> wrote: > David Brown <david.brown@hesbynett.no> writes: >> On 11/01/17 22:38, Gareth Owen wrote: >>> BartC <bc@freeuk.com> writes: >>>> It just reinforces my point that strcmp by itself is unintuitive. >> >> I would say that strcmp is a useful function, but the name is not ideal. >> It would make more sense, IMHO, if it were called "strdiff". > > strdiff would be a good name for a function that returns a Boolean > result indicating whether its argument strings differ. strcmp can > be used that way, but IMHO the name strdiff would be more misleading > than strcmp. What it really does is *compare* two strings. > > It's nice for a function that returns a result to have a name > that relfects the meaning of that result, but it's not always > practical. And in the case of strcmp, you can think of the > negative/zero/positive result it returns as a *comparison*, which > makes the name strcmp, perfectly sensible. It's not the most > intuitive name, but it's more than good enough. What would be more intuitive? (Maybe you're just being polite?) The spaceship operator (<=>) in Perl is used to test whether one number is less-than, equal-to, or greater-than another number. In other languages it's called the three-way comparison operator. The equivalent string operator in Perl is literally "cmp". The cmp operator, like strcmp, is a lexical comparison of strings. strdiff sounds odd to me. A comparison with a boolean result is normally phrased as a test for equality. The _difference_ of two things typically comes neither from a boolean set (like for equality) nor ternary set (like for the three-way comparison). > (A somewhat irrelevant example: the Unix "diff" command returns > a result indicating success if the two files do *not* differ. > That probably bothered me for a couple of minutes when I first > learned about it.) > So does the cmp(1) utility, which likewise gives me pause everytime I use it. More so than diff as I tend to use diff interactively, ignoring the exit code. Whereas I use cmp -s just for the exit code. It doesn't help (my confusion, nor this discussion!) that in the Unix shell an exit status of 0 evaluates as true, and non-0 as false. It strikes me that your example of diff may not only be relevant, but perhaps be one of the most relevant observations in this thread! - Bill
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standard error codes Thiago Adams <thiago.adams@gmail.com> - 2017-01-08 06:34 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-08 11:05 -0800
Re: standard error codes Thiago Adams <thiago.adams@gmail.com> - 2017-01-09 03:33 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-09 04:55 -0800
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-09 09:06 -0800
Re: standard error codes Thiago Adams <thiago.adams@gmail.com> - 2017-01-09 09:52 -0800
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-09 21:50 +0000
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-09 22:36 +0000
Re: standard error codes supercat@casperkitty.com - 2017-01-09 14:51 -0800
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-09 23:39 +0000
Re: standard error codes supercat@casperkitty.com - 2017-01-09 15:51 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-09 16:08 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-09 18:51 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-10 02:02 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-10 07:34 -0800
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-10 01:39 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-10 09:07 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-10 09:59 -0800
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-10 12:02 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-10 12:53 -0800
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-10 13:03 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-10 15:41 -0800
Re: standard error codes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-11 02:56 +0000
Re: standard error codes supercat@casperkitty.com - 2017-01-11 07:42 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-10 12:59 -0800
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-10 18:14 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-10 12:12 -0800
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-10 20:35 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-10 13:00 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-11 08:16 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-11 18:25 +0000
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-11 19:09 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-11 12:03 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-11 20:10 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-11 12:19 -0800
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-11 20:31 +0000
Re: standard error codes Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2017-01-11 15:32 -0500
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-11 20:48 +0000
Re: standard error codes Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2017-01-11 15:58 -0500
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-11 13:01 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-11 21:05 +0000
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-11 21:08 +0000
Re: standard error codes Gareth Owen <gwowen@gmail.com> - 2017-01-11 21:38 +0000
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-11 21:58 +0000
Re: standard error codes David Brown <david.brown@hesbynett.no> - 2017-01-12 12:11 +0100
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-12 09:28 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-12 18:06 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-12 11:39 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-12 19:50 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-12 13:03 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-12 21:13 +0000
Re: standard error codes <william@wilbur.25thandClement.com> - 2017-01-12 20:00 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-13 01:56 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-13 12:54 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-13 09:35 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-13 17:38 +0000
Re: standard error codes James Kuyper <jameskuyper@verizon.net> - 2017-01-13 13:06 -0500
Re: standard error codes raltbos@xs4all.nl (Richard Bos) - 2017-01-18 12:00 +0000
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-18 12:13 +0000
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-12 16:43 -0800
Re: standard error codes <william@wilbur.25thandClement.com> - 2017-01-12 19:34 -0800
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-13 09:27 -0800
Re: standard error codes raltbos@xs4all.nl (Richard Bos) - 2017-01-12 19:33 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-12 12:10 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-11 11:50 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-11 20:38 +0000
Re: standard error codes jadill33@gmail.com - 2017-01-11 12:26 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-11 20:44 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-09 09:03 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-08 11:40 -0800
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