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| From | Melzzzzz <mel@zzzzz.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Extending C with GC? |
| Date | 2016-08-27 00:41 +0200 |
| Organization | albasani.net |
| Message-ID | <20160827004114.174b6dd2@maxa-pc> (permalink) |
| References | (6 earlier) <no1j8u$aja$2@dont-email.me> <npargh$151$1@z-news.wcss.wroc.pl> <47d3538c-2ec3-4109-b049-0d9ae80deebe@googlegroups.com> <863e6b53-86c5-4335-8f82-98be88d6e589@googlegroups.com> <e77a0fb9-ef4a-43fa-8d6b-2ed22ba7df54@googlegroups.com> |
On Fri, 26 Aug 2016 13:37:58 -0700 (PDT)
supercat@casperkitty.com wrote:
> On Friday, August 26, 2016 at 4:24:54 AM UTC-5, Öö Tiib wrote:
> > On Monday, 22 August 2016 18:46:15 UTC+3, supe...@casperkitty.com
> > wrote:
> > >
> > > C does not presently have any concept of unions that are
> > > discrimitated in such fashion, but most C++ implementations do
> > > [if a type with virtual methods has several types derived from
> > > it, a pointer to the original type will behave as a pointer to a
> > > union containing that type and all derived types].
> >
> > What you claim is like claiming that pointer to struct that contains
> > 'int' member is pointer to 'int'.
>
> If `class foo` contains virtual methods, the compiler will generally
> have to store for every instance of any class derived from it
> information sufficient to distinguish among all possible derived
> types in all cases where it may affect how a virtual method gets
> dispatched. The compiler is not required to make that information
> available to the programmer, and could omit it if it could statically
> determine the effect of every virtual method call, but the idea that
> compilers may, at their leisure, store some kind of type-related
> information within objects has always been part of C++.
>
> > Yes if we have 'struct X {int val; int *p; };' then at address of
> > that struct there is required to be 'int' object but that is
> > because int member was very first member.
> >
> > In C++ we can have multiple base classes and if those contain data
> > then according sub-objects can't all be the very first things in
> > derived class object.
>
> My point was that a C++ compiler is allowed to, at its leisure,
> include type-related within objects; if the type system had different
> types for "pointer to an object with a type descriptor" and "pointer
> to something that does not contain any pointers to objects with type
> descriptors", and if objects with type descriptors could not be
> treated as sequences of bytes, then a GC could identify every pointer
> that could ever be reachable.
>
You miss the whole point. GC works with chunks of data. What GC needs
is special pointer type that will register itself to GC or have some
additional data so that GC can distinguish what is pointer and what is
not.
C++ pointers (except member pointers) are just ones like in C.
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Extending C with GC? luser droog <luser.droog@gmail.com> - 2016-07-31 15:31 -0700
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-07-31 15:52 -0700
Re: Extending C with GC? Tim Rentsch <txr@alumni.caltech.edu> - 2016-07-31 17:21 -0700
Re: Extending C with GC? Jean-Marc Bourguet <jm@bourguet.org> - 2016-08-01 20:34 +0200
Re: Extending C with GC? supercat@casperkitty.com - 2016-08-01 12:14 -0700
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-01 12:46 -0700
Re: Extending C with GC? "James R. Kuyper" <jameskuyper@verizon.net> - 2016-08-01 15:56 -0400
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-01 14:28 -0700
Re: Extending C with GC? Jean-Marc Bourguet <jm@bourguet.org> - 2016-08-01 23:37 +0200
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-01 15:03 -0700
Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-02 00:11 +0200
Re: Extending C with GC? "James R. Kuyper" <jameskuyper@verizon.net> - 2016-08-01 18:19 -0400
Re: Extending C with GC? BGB <cr88192@hotmail.com> - 2016-08-02 12:46 -0500
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-03 15:26 -0700
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-03 15:49 -0700
Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-04 14:07 +1200
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-03 19:26 -0700
Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-04 14:55 +1200
Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-03 20:38 -0700
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-04 05:10 -0700
Re: Extending C with GC? Siri Cruise <chine.bleu@yahoo.com> - 2016-08-04 05:57 -0700
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-04 06:13 -0700
Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-05 07:24 +1200
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-04 12:47 -0700
Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-04 23:32 -0700
Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-05 10:09 +0100
Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-05 20:32 +1200
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-05 06:14 -0700
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 04:14 -0700
Re: Extending C with GC? Melzzzzz <mel@zzzzz.com> - 2016-08-06 13:23 +0200
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 04:38 -0700
Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-06 04:34 -0700
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 05:28 -0700
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 06:05 -0700
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 06:12 -0700
Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-06 14:02 +0100
Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-06 06:11 -0700
Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-06 14:50 +0100
Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-06 07:57 -0700
Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-06 17:02 +0100
Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-06 19:20 +0200
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-06 14:27 +0100
Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-06 14:45 +0100
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 09:59 -0700
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-06 19:38 +0100
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 17:03 -0700
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 09:54 +0100
Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-07 21:53 +1200
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 11:34 +0100
Re: Extending C with GC? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-08-07 12:06 +0000
Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-07 14:10 +0100
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 15:38 +0100
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-07 14:32 -0700
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 23:44 +0100
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-07 16:12 -0700
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 01:42 +0100
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-07 18:56 -0700
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 10:20 +0100
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-08 09:39 -0700
Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-08 02:30 +0100
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 20:15 +0100
Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-08 01:24 +0100
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 02:08 +0100
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-07 18:49 -0700
Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-08 03:28 +0100
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 12:14 +0100
Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 07:37 +1200
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 20:56 +0100
Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 08:11 +1200
Re: Extending C with GC? Melzzzzz <mel@zzzzz.com> - 2016-08-07 22:19 +0200
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 22:23 +0100
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-07 14:29 -0700
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 22:36 +0100
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-07 15:04 -0700
Re: Extending C with GC? jameskuyper@verizon.net - 2016-08-07 15:19 -0700
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 00:04 +0100
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-07 16:20 -0700
Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 15:21 +1200
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 10:35 +0100
Re: Extending C with GC? Gareth Owen <gwowen@gmail.com> - 2016-08-08 18:13 +0100
Re: Extending C with GC? supercat@casperkitty.com - 2016-08-08 11:53 -0700
Re: Extending C with GC? raltbos@xs4all.nl (Richard Bos) - 2016-08-10 12:58 +0000
Re: Extending C with GC? supercat@casperkitty.com - 2016-08-10 07:05 -0700
Re: Extending C with GC? Ken Brody <kenbrody@spamcop.net> - 2016-08-10 12:29 -0400
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 21:15 +0100
Re: Extending C with GC? supercat@casperkitty.com - 2016-08-08 08:57 -0700
Re: Extending C with GC? luser droog <luser.droog@gmail.com> - 2016-08-07 15:37 -0700
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-07 14:58 -0700
Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 15:26 +1200
Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-08 10:26 +0200
Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 21:13 +1200
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 10:41 +0100
Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-08 12:00 +0200
Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 22:07 +1200
Re: Extending C with GC? David Brown <david.brown@hesbynett.no> - 2016-08-08 12:57 +0200
Re: Extending C with GC? Gareth Owen <gwowen@gmail.com> - 2016-08-08 18:12 +0100
Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 21:25 +1200
Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-08 02:57 -0700
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-07 13:28 -0700
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-07 05:42 -0700
Re: Extending C with GC? Florian Weimer <fw@deneb.enyo.de> - 2016-08-07 11:49 +0200
Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-06 19:18 +0200
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-06 12:35 -0700
Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-06 19:27 +0200
Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 10:55 -0700
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-06 12:31 -0700
Re: Extending C with GC? James Kuyper <jameskuyper@verizon.net> - 2016-08-03 22:36 -0400
Re: Extending C with GC? David Brown <david.brown@hesbynett.no> - 2016-08-04 10:57 +0200
Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-04 04:09 -0700
Re: Extending C with GC? David Brown <david.brown@hesbynett.no> - 2016-08-04 14:01 +0200
Re: Extending C with GC? supercat@casperkitty.com - 2016-08-04 07:52 -0700
Re: Extending C with GC? Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-04 08:57 -0700
Re: Extending C with GC? supercat@casperkitty.com - 2016-08-04 09:19 -0700
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-04 12:30 -0700
Re: Extending C with GC? supercat@casperkitty.com - 2016-08-04 15:21 -0700
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-04 16:50 -0700
Re: Extending C with GC? supercat@casperkitty.com - 2016-08-05 07:31 -0700
Re: Extending C with GC? Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-05 16:01 -0700
Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-04 21:00 +0200
Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-04 20:26 +0100
Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-05 10:37 +0200
Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-05 15:52 +0100
Re: Extending C with GC? antispam@math.uni.wroc.pl - 2016-08-21 00:09 +0000
Re: Extending C with GC? Gareth Owen <gwowen@gmail.com> - 2016-08-21 08:58 +0100
Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-21 10:48 +0200
Re: Extending C with GC? "Pascal J. Bourguignon" <pjb@informatimago.com> - 2016-08-21 19:58 +0200
Re: Extending C with GC? supercat@casperkitty.com - 2016-08-22 08:46 -0700
Re: Extending C with GC? Öö Tiib <ootiib@hot.ee> - 2016-08-26 02:24 -0700
Re: Extending C with GC? supercat@casperkitty.com - 2016-08-26 13:37 -0700
Re: Extending C with GC? Melzzzzz <mel@zzzzz.com> - 2016-08-27 00:41 +0200
Re: Extending C with GC? Öö Tiib <ootiib@hot.ee> - 2016-08-28 06:12 -0700
Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-05 10:06 +0100
Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-05 15:26 +0100
Re: Extending C with GC? Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-05 08:11 -0700
Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-05 17:43 +0200
Re: Extending C with GC? Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-05 15:28 -0700
Re: Extending C with GC? BGB <cr88192@hotmail.com> - 2016-08-04 17:11 -0500
Re: Extending C with GC? Tim Rentsch <txr@alumni.caltech.edu> - 2016-07-31 17:35 -0700
Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-01 07:45 +0200
Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-01 08:49 -0700
Re: Extending C with GC? supercat@casperkitty.com - 2016-08-01 09:06 -0700
Re: Extending C with GC? Aleksandar Kuktin <akuktin@gmail.com> - 2016-08-05 18:11 +0000
Re: Extending C with GC? luser droog <luser.droog@gmail.com> - 2016-08-05 11:24 -0700
Re: Extending C with GC? "Chris M. Thomasson" <invalid@invalid.invalid> - 2016-08-08 22:12 -0700
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