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Groups > comp.lang.c > #103469
| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: How to compile several C files |
| Date | 2017-02-08 15:01 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <87d1esafr0.fsf@bsb.me.uk> (permalink) |
| References | (4 earlier) <5b6f9245-8bdf-4365-8a73-201c192f6980@googlegroups.com> <o7cvk5$hmt$1@dont-email.me> <8760klby18.fsf@bsb.me.uk> <o7erj0$1ob$1@dont-email.me> <o7f1q1$m6q$1@dont-email.me> |
Richard Heathfield <rjh@cpax.org.uk> writes:
<snip>
> Yes. Sometimes one has no choice - one arrives on a project to find
> that they /already/ have a zillion such identifiers, and there isn't
> the time or the budget to fix the problem (although there always seems
> to be plenty of time and budget to fix the second-generation problems
> that ensue!).
>
> I /have/ defined a file scope non-const with external linkage in real
> world code. Once ever, I think. It was very, very evil, but for that
> particular project it was still the lesser of two evils.
It would help to be able to use const data more often but C has a
problem here: you can't alter a const object without undefined
behaviour, and you don't always have the right value at the point of
definition. For example, you might want to say
const char *const program_name;
so that your error reporting module can use it. But in main() you'd
have to write
program_name = argv[0] ? argv[0] : "unknown program";
and, of course, you can't.
You could (and I have done) any of these:
(a) provide a function const char *program_name(void); which will give
you a lot of flexibility in the future but can seem a little over
the top for simple programs.
(b) static const char *local_program_name;
const char *const *const program_name = &local_program_name;
and use *program_name outside of the main translation unit.
(c) break the type rules.
(d) just allow extern const *program_name;
What do you (generic you -- all of you) like to do in these situations?
(This example is many not a good one -- please suggest others where
you've wanted to share unchanging data between TUs.)
> The
> alternative was to add an extra parameter to every single function in
> the library, and that included rewriting qsort() and bsearch() to
> support comparison functions with three parameters.
I've had a similar situation but you don't (always) have to re-write
qsort and bsearch. You can put a pointer to the configuration (or
whatever is it) into a static file-scope object just before the qsort
call and, just to be safe, you can nullify it after. If the qsort call
is separated form the comparison function definition you will be forced
to use an extern pointer, but the danger becomes very limited -- only
for the length of the sort is the data globally available.
--
Ben.
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How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 06:10 -0800
Re: How to compile several C files Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-02-07 07:02 -0800
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-07 16:03 +0100
Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-07 15:06 +0000
Re: How to compile several C files BartC <bc@freeuk.com> - 2017-02-07 15:14 +0000
Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-07 16:02 +0000
Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 15:42 +0000
Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-07 16:19 +0000
Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 16:40 +0000
Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-07 17:16 +0000
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 10:19 +0100
Re: How to compile several C files "James R. Kuyper" <jameskuyper@verizon.net> - 2017-02-07 11:51 -0500
Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 08:26 -0800
Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 16:42 +0000
Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 10:14 -0800
Re: How to compile several C files vitale.alla@gmail.com - 2017-02-16 09:49 -0800
Re: How to compile several C files Ian Collins <ian-news@hotmail.com> - 2017-02-08 17:35 +1300
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 10:28 +0100
Re: How to compile several C files Ian Collins <ian-news@hotmail.com> - 2017-02-08 22:43 +1300
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 11:29 +0100
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 10:14 +0100
Re: How to compile several C files James Kuyper <jameskuyper@verizon.net> - 2017-02-07 10:07 -0500
Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 07:56 -0800
Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 08:24 -0800
Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-07 16:44 +0000
Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 08:54 -0800
Re: How to compile several C files "James R. Kuyper" <jameskuyper@verizon.net> - 2017-02-07 12:20 -0500
Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 10:05 -0800
Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 18:27 +0000
Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 18:40 +0000
Re: How to compile several C files Keith Thompson <kst-u@mib.org> - 2017-02-07 12:22 -0800
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 10:33 +0100
Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-08 10:25 -0800
Re: How to compile several C files Keith Thompson <kst-u@mib.org> - 2017-02-07 08:58 -0800
Re: How to compile several C files "James R. Kuyper" <jameskuyper@verizon.net> - 2017-02-07 12:07 -0500
Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 09:14 -0800
Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 17:21 +0000
Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 10:14 -0800
Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 10:28 -0800
Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 18:43 +0000
Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 10:55 -0800
Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-07 19:28 +0000
Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 19:51 +0000
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 11:25 +0100
Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-08 12:11 +0000
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 14:58 +0100
Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-08 14:23 +0000
Re: How to compile several C files supercat@casperkitty.com - 2017-02-08 07:48 -0800
Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-08 16:09 +0000
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 17:23 +0100
Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 15:01 +0000
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 17:22 +0100
Re: How to compile several C files Keith Thompson <kst-u@mib.org> - 2017-02-08 09:27 -0800
Re: How to compile several C files supercat@casperkitty.com - 2017-02-08 09:51 -0800
Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 21:06 +0000
Re: How to compile several C files supercat@casperkitty.com - 2017-02-08 13:20 -0800
Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 21:40 +0000
Re: How to compile several C files supercat@casperkitty.com - 2017-02-08 13:49 -0800
Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 23:09 +0000
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 23:25 +0100
Re: How to compile several C files supercat@casperkitty.com - 2017-02-08 15:17 -0800
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-09 01:17 +0100
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 23:19 +0100
Re: How to compile several C files Keith Thompson <kst-u@mib.org> - 2017-02-08 16:44 -0800
Re: How to compile several C files Tim Rentsch <txr@alumni.caltech.edu> - 2017-02-08 22:32 -0800
Re: How to compile several C files Robert Wessel <robertwessel2@yahoo.com> - 2017-02-09 04:03 -0600
Re: How to compile several C files Ian Collins <ian-news@hotmail.com> - 2017-02-10 07:52 +1300
Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 12:12 +0000
Re: How to compile several C files BartC <bc@freeuk.com> - 2017-02-08 13:09 +0000
Re: How to compile several C files Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-02-08 05:14 -0800
Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 15:32 +0000
Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 15:09 +0100
Re: How to compile several C files Keith Thompson <kst-u@mib.org> - 2017-02-07 09:22 -0800
Re: How to compile several C files Gareth Owen <gwowen@gmail.com> - 2017-02-07 18:29 +0000
Re: How to compile several C files bart4858@gmail.com - 2017-02-07 11:05 -0800
Re: How to compile several C files Keith Thompson <kst-u@mib.org> - 2017-02-07 12:26 -0800
Re: How to compile several C files Barry Schwarz <schwarzb@dqel.com> - 2017-02-07 08:34 -0800
Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 08:57 -0800
Re: How to compile several C files "James R. Kuyper" <jameskuyper@verizon.net> - 2017-02-07 12:29 -0500
Re: How to compile several C files Manfred <noname@invalid.add> - 2017-02-07 19:02 +0100
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