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| From | Ian Collins <ian-news@hotmail.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Is enum a suitable way to implement a "local define?" |
| Date | 2014-04-07 23:00 +1200 |
| Message-ID | <bqfeqaF4crdU2@mid.individual.net> (permalink) |
| References | (6 earlier) <lhti9s$vg9$1@dont-email.me> <bqf2nbFtpsdU2@mid.individual.net> <P4u0v.97227$%U7.68280@fx05.am4> <bqfadrF4crdU1@mid.individual.net> <mLu0v.35453$2w4.14416@fx17.am4> |
BartC wrote:
> "Ian Collins" <ian-news@hotmail.com> wrote in message
> news:bqfadrF4crdU1@mid.individual.net...
>> BartC wrote:
>
>>> I thought it would go without saying that in a feature such as:
>>>
>>> constant name = value;
>>>
>>> that 'value' would have to be an expression. Otherwise it would have
>>> bigger
>>> limitations than any of #define, enum or const.
>>>
>>> Obviously the expression can only includes terms that are actual
>>> constants,
>>> or previous named constants.
>>
>> Too restrictive, the constexpr may also be a function, the only
>> restriction is it has to be able to be evaluated at compile time.
>
> Too restrictive? Until now, we haven't even been able to define "constant
> a=1;"!
>
> Being able to evaluate absolutely anything at compile-time is far too
> open-ended a feature, but then that is to be expected if coming from a C++.
There is only so much that can be evaluated at compile time and C++
already had rules for this. The advantage of constexpr is you can use
it to force evaluation at compile time (to use read only memory), rather
than relying on optimisation (which probably won't use read only
memory). In the embedded world, that certainty is important.
For example, something like:
constexpr int f( int a, int b, int c ) { return (a+b)/c; }
int main()
{
constexpr int n = f( 2,3,4 );
}
Will guarantee n is a compile time constant.
If you want to do more open ended things at compile time, you have to
become a master of the black art of template meta-programming!
--
Ian Collins
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Is enum a suitable way to implement a "local define?" partremmaps@gmail.com - 2014-04-05 13:07 -0700
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-05 13:55 -0700
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-05 14:14 -0700
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-06 22:18 +0200
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-06 13:28 -0700
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-06 16:35 -0400
Re: Is enum a suitable way to implement a "local define?" Ian Collins <ian-news@hotmail.com> - 2014-04-07 08:55 +1200
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-06 23:30 +0200
Re: Is enum a suitable way to implement a "local define?" Ian Collins <ian-news@hotmail.com> - 2014-04-07 10:12 +1200
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-06 18:22 -0400
Re: Is enum a suitable way to implement a "local define?" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-05 14:30 -0700
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-05 22:39 +0100
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-06 22:27 +0200
Re: Is enum a suitable way to implement a "local define?" Ian Collins <ian-news@hotmail.com> - 2014-04-07 08:52 +1200
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-06 23:20 +0100
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-07 02:17 +0200
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-06 19:00 -0700
Re: Is enum a suitable way to implement a "local define?" glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-07 04:44 +0000
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-07 10:15 +0100
Re: Is enum a suitable way to implement a "local define?" glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-07 18:32 +0000
Re: Is enum a suitable way to implement a "local define?" Kaz Kylheku <kaz@kylheku.com> - 2014-04-07 18:47 +0000
Re: Is enum a suitable way to implement a "local define?" Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-04-07 11:39 +0200
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-07 08:58 +0200
Re: Is enum a suitable way to implement a "local define?" Ian Collins <ian-news@hotmail.com> - 2014-04-07 19:34 +1200
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-07 09:41 +0100
Re: Is enum a suitable way to implement a "local define?" Ian Collins <ian-news@hotmail.com> - 2014-04-07 21:45 +1200
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-07 11:03 +0100
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-07 12:54 +0200
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-07 13:48 +0100
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-07 15:27 +0200
Re: Is enum a suitable way to implement a "local define?" Ian Collins <ian-news@hotmail.com> - 2014-04-07 23:00 +1200
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-07 11:31 +0200
Re: Is enum a suitable way to implement a "local define?" Les Cargill <lcargill99@comcast.com> - 2014-04-07 07:24 -0500
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-07 15:02 +0200
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-07 10:19 +0100
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-07 12:43 +0200
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-07 13:27 +0100
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-07 15:16 +0200
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-07 14:43 +0100
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-07 16:44 +0200
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-07 16:52 +0100
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-07 12:53 -0400
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-07 12:59 -0400
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-07 18:12 +0100
Re: Is enum a suitable way to implement a "local define?" Richard <rgrdev_@gmail.com> - 2014-04-07 18:27 +0100
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-08 23:22 +0100
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-08 18:44 -0400
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-09 00:22 +0100
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-08 09:39 +0200
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-08 23:27 +0100
Re: Is enum a suitable way to implement a "local define?" Ian Collins <ian-news@hotmail.com> - 2014-04-09 10:52 +1200
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-09 00:24 +0100
Re: Is enum a suitable way to implement a "local define?" Ian Collins <ian-news@hotmail.com> - 2014-04-09 11:32 +1200
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-09 08:58 +0200
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-08 19:54 -0400
Re: Is enum a suitable way to implement a "local define?" Kaz Kylheku <kaz@kylheku.com> - 2014-04-09 00:41 +0000
Re: Is enum a suitable way to implement a "local define?" glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-08 23:05 +0000
Re: Is enum a suitable way to implement a "local define?" Stephen Sprunk <stephen@sprunk.org> - 2014-04-08 18:24 -0500
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-08 19:39 -0400
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-08 22:41 -0700
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-09 09:16 +0200
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-09 07:27 -0400
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-09 15:32 +0200
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-09 08:32 -0700
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-10 11:03 +0200
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-10 07:27 -0400
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-10 14:02 +0200
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-10 08:34 -0700
Re: Is enum a suitable way to implement a "local define?" glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-10 16:36 +0000
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-10 12:58 -0400
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-09 11:36 -0400
Re: Is enum a suitable way to implement a "local define?" glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-09 18:36 +0000
Re: Is enum a suitable way to implement a "local define?" Stephen Sprunk <stephen@sprunk.org> - 2014-04-09 14:11 -0500
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-10 13:55 +0200
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-09 02:35 +0200
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-08 23:05 -0700
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-09 09:45 +0200
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-09 08:19 -0700
Re: Is enum a suitable way to implement a "local define?" Richard <rgrdev_@gmail.com> - 2014-04-10 09:08 +0100
Re: Is enum a suitable way to implement a "local define?" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-10 02:57 -0700
Re: Is enum a suitable way to implement a "local define?" Richard <rgrdev_@gmail.com> - 2014-04-10 11:50 +0100
Re: Is enum a suitable way to implement a "local define?" Seungbeom Kim <musiphil@bawi.org> - 2014-04-10 11:37 -0700
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-10 14:52 -0400
Re: Is enum a suitable way to implement a "local define?" Kaz Kylheku <kaz@kylheku.com> - 2014-04-10 18:53 +0000
Re: Is enum a suitable way to implement a "local define?" glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-10 19:36 +0000
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-10 15:59 -0400
Re: Is enum a suitable way to implement a "local define?" glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-10 20:12 +0000
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-10 16:18 -0400
Re: Is enum a suitable way to implement a "local define?" Martin Shobe <martin.shobe@yahoo.com> - 2014-04-11 10:24 -0500
Re: Is enum a suitable way to implement a "local define?" Martin Shobe <martin.shobe@yahoo.com> - 2014-04-11 14:36 -0500
Re: Is enum a suitable way to implement a "local define?" David Thompson <dave.thompson2@verizon.net> - 2014-05-25 16:44 -0400
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-10 12:47 -0700
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-10 16:05 -0400
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-10 13:34 -0700
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-10 16:59 -0400
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-10 16:01 -0700
Re: Is enum a suitable way to implement a "local define?" Tim Rentsch <txr@alumni.caltech.edu> - 2014-04-14 21:24 -0700
Re: Is enum a suitable way to implement a "local define?" Tim Rentsch <txr@alumni.caltech.edu> - 2014-04-14 21:36 -0700
Re: Is enum a suitable way to implement a "local define?" glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-15 05:26 +0000
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-15 07:18 -0400
Re: Is enum a suitable way to implement a "local define?" Tim Rentsch <txr@alumni.caltech.edu> - 2014-04-18 09:01 -0700
Please ignore trolls Noob <root@127.0.0.1> - 2014-04-09 15:26 +0200
Re: Please ignore trolls David Brown <david.brown@hesbynett.no> - 2014-04-09 15:38 +0200
Re: Please ignore trolls James Kuyper <jameskuyper@verizon.net> - 2014-04-09 12:02 -0400
Re: Please ignore trolls Kaz Kylheku <kaz@kylheku.com> - 2014-04-09 19:18 +0000
Re: Please ignore trolls "BartC" <bc@freeuk.com> - 2014-04-10 20:18 +0100
Re: Please ignore trolls James Kuyper <jameskuyper@verizon.net> - 2014-04-10 15:49 -0400
Re: Please ignore trolls gazelle@shell.xmission.com (Kenny McCormack) - 2014-04-10 20:14 +0000
Re: Please ignore trolls "BartC" <bc@freeuk.com> - 2014-04-11 14:35 +0100
Re: Please ignore trolls Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-11 07:35 -0700
Re: Please ignore trolls "BartC" <bc@freeuk.com> - 2014-04-11 15:51 +0100
Re: Please ignore trolls Jorgen Grahn <grahn+nntp@snipabacken.se> - 2014-04-12 15:48 +0000
Re: Please ignore trolls Kaz Kylheku <kaz@kylheku.com> - 2014-04-10 21:16 +0000
Re: Please ignore trolls "BartC" <bc@freeuk.com> - 2014-04-12 15:35 +0100
Re: Please ignore trolls Keith Thompson <kst-u@mib.org> - 2014-04-09 08:03 -0700
Re: Please ignore trolls gazelle@shell.xmission.com (Kenny McCormack) - 2014-04-09 15:25 +0000
Re: Is enum a suitable way to implement a "local define?" Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-04-09 21:28 +0100
Re: Is enum a suitable way to implement a "local define?" Ian Collins <ian-news@hotmail.com> - 2014-04-10 08:39 +1200
Re: Is enum a suitable way to implement a "local define?" Kaz Kylheku <kaz@kylheku.com> - 2014-04-09 23:38 +0000
Re: Is enum a suitable way to implement a "local define?" Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-04-10 02:07 +0100
Re: Is enum a suitable way to implement a "local define?" Ike Naar <ike@iceland.freeshell.org> - 2014-04-09 05:18 +0000
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-09 08:05 -0700
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-07 08:33 -0700
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-07 17:16 +0100
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-07 11:07 -0700
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-08 09:49 +0200
Re: Is enum a suitable way to implement a "local define?" Ian Collins <ian-news@hotmail.com> - 2014-04-08 20:33 +1200
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-08 12:31 +0200
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-08 21:59 -0400
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-08 07:37 -0700
Re: Is enum a suitable way to implement a "local define?" Stephen Sprunk <stephen@sprunk.org> - 2014-04-08 08:35 -0500
Re: Is enum a suitable way to implement a "local define?" Seungbeom Kim <musiphil@bawi.org> - 2014-04-08 11:30 -0700
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-08 23:46 +0100
Re: Is enum a suitable way to implement a "local define?" Stephen Sprunk <stephen@sprunk.org> - 2014-04-08 18:28 -0500
Re: Is enum a suitable way to implement a "local define?" Seungbeom Kim <musiphil@bawi.org> - 2014-04-08 17:21 -0700
Re: Is enum a suitable way to implement a "local define?" "BartC" <bc@freeuk.com> - 2014-04-09 09:07 +0100
Re: Is enum a suitable way to implement a "local define?" James Kuyper <jameskuyper@verizon.net> - 2014-04-09 07:22 -0400
Re: Is enum a suitable way to implement a "local define?" Keith Thompson <kst-u@mib.org> - 2014-04-06 16:25 -0700
Re: Is enum a suitable way to implement a "local define?" David Brown <david.brown@hesbynett.no> - 2014-04-07 02:22 +0200
Re: Is enum a suitable way to implement a "local define?" Ike Naar <ike@iceland.freeshell.org> - 2014-04-06 06:08 +0000
Re: Is enum a suitable way to implement a "local define?" jacob navia <jacob@spamsink.net> - 2014-04-06 08:54 +0200
Re: Is enum a suitable way to implement a "local define?" partremmaps@gmail.com - 2014-04-07 23:48 -0700
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