Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Learning functions; roots of the quadratic; two return values |
| Date | 2015-10-04 18:24 -0700 |
| Organization | None to speak of |
| Message-ID | <lnoageumxk.fsf@kst-u.example.com> (permalink) |
| References | (4 earlier) <8737xrpwf0.fsf@bsb.me.uk> <mupfr1$3l1$1@dont-email.me> <87oagfobcl.fsf@bsb.me.uk> <lnvbamxv9a.fsf@kst-u.example.com> <87mvvyky8c.fsf@bsb.me.uk> |
Ben Bacarisse <ben.usenet@bsb.me.uk> writes:
> Keith Thompson <kst-u@mib.org> writes:
[...]
>> Returning a structure that contains an array creates an object with
>> *temporary lifetime*, a concept that wasn't introduced until C11.
>
> I was not aware of that change. I'll go have a look. Thanks.
>
>> In C99 and earlier, something like
>>
>> f1(1.5).r[0]
>>
>> has undefined, or at least vaguely defined, behavior. Array indexing
>> requires an array object, but prior to c11 there is no array object to
>> be indexed, just an array value that's part of the returned struct
>> value.
>
> Presumably, in C99, similar problems can occur when a function returns a
> union since the re-interpretation that's been discussed elsewhere
> requires and object representation and not simply a value.
Yes, it applies to both structures and unions.
N1570 6.2.4p8:
A non-lvalue expression with structure or union type, where
the structure or union contains a member with array type
(including, recursively, members of all contained structures
and unions) refers to an object with automatic storage
duration and *temporary lifetime*. Its lifetime begins when
the expression is evaluated and its initial value is the value
of the expression. Its lifetime ends when the evaluation of
the containing full expression or full declarator ends. Any
attempt to modify an object with temporary lifetime results in
undefined behavior.
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Learning functions; roots of the quadratic; two return values Alla _ <modelling.data@gmail.com> - 2015-10-03 10:43 -0700
Re: Learning functions; roots of the quadratic; two return values Andrew Cooper <amc96@cam.ac.uk> - 2015-10-03 19:00 +0100
Re: Learning functions; roots of the quadratic; two return values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-03 19:34 +0100
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-03 21:29 +0200
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-03 21:36 +0200
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-03 21:43 +0200
Re: Learning functions; roots of the quadratic; two return values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-03 20:46 +0100
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-03 22:46 +0200
Re: Learning functions; roots of the quadratic; two return values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-03 23:18 +0100
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-04 01:08 +0200
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-04 01:36 +0200
Re: Learning functions; roots of the quadratic; two return values Ian Collins <ian-news@hotmail.com> - 2015-10-04 12:52 +1300
Re: Learning functions; roots of the quadratic; two return values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-04 15:42 +0100
Re: Learning functions; roots of the quadratic; two return values jacobnavia <jacob@jacob.remcomp.fr> - 2015-10-03 23:05 +0200
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-03 23:41 +0200
Re: Learning functions; roots of the quadratic; two return values jacobnavia <jacob@jacob.remcomp.fr> - 2015-10-04 00:14 +0200
Re: Learning functions; roots of the quadratic; two return values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-03 23:07 +0100
Re: Learning functions; roots of the quadratic; two return values jacobnavia <jacob@jacob.remcomp.fr> - 2015-10-04 00:32 +0200
Re: Learning functions; roots of the quadratic; two return values Keith Thompson <kst-u@mib.org> - 2015-10-04 12:56 -0700
Re: Learning functions; roots of the quadratic; two return values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-04 23:41 +0100
Re: Learning functions; roots of the quadratic; two return values Keith Thompson <kst-u@mib.org> - 2015-10-04 18:24 -0700
Re: Learning functions; roots of the quadratic; two return values James Kuyper <jameskuyper@verizon.net> - 2015-10-04 16:36 -0400
Re: Learning functions; roots of the quadratic; two return values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-05 00:01 +0100
Re: Learning functions; roots of the quadratic; two return values James Kuyper <jameskuyper@verizon.net> - 2015-10-04 19:24 -0400
Re: Learning functions; roots of the quadratic; two return values Ian Collins <ian-news@hotmail.com> - 2015-10-04 10:18 +1300
Re: Learning functions; roots of the quadratic; two return values jacobnavia <jacob@jacob.remcomp.fr> - 2015-10-03 23:27 +0200
Re: Learning functions; roots of the quadratic; two return values Ian Collins <ian-news@hotmail.com> - 2015-10-04 11:08 +1300
Re: Learning functions; roots of the quadratic; two return values Richard Damon <Richard@Damon-Family.org> - 2015-10-03 18:38 -0400
Re: Learning functions; roots of the quadratic; two return values Ian Collins <ian-news@hotmail.com> - 2015-10-04 11:47 +1300
Re: Learning functions; roots of the quadratic; two return values raltbos@xs4all.nl (Richard Bos) - 2015-10-04 14:07 +0000
Re: Learning functions; roots of the quadratic; two return values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-04 15:48 +0100
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-04 18:59 +0200
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-04 20:06 +0200
Re: Learning functions; roots of the quadratic; two return values Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-04 15:21 -0700
Re: Learning functions; roots of the quadratic; two return values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-05 05:25 +0000
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-03 21:48 +0200
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-04 00:31 +0200
Re: Learning functions; roots of the quadratic; two return values alla.rashitova@gmail.com - 2015-10-05 08:40 -0700
Re: Learning functions; roots of the quadratic; two return values Richard Heathfield <rjh@cpax.org.uk> - 2015-10-05 17:10 +0100
Re: Learning functions; roots of the quadratic; two return values Barry Schwarz <schwarzb@dqel.com> - 2015-10-05 10:41 -0700
Re: Learning functions; roots of the quadratic; two return values "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-03 12:04 -0700
Re: Learning functions; roots of the quadratic; two return values Philip Lantz <prl@canterey.us> - 2015-10-03 12:48 -0700
Re: Learning functions; roots of the quadratic; two return values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-03 20:55 +0100
Re: Learning functions; roots of the quadratic; two return values "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-03 13:27 -0700
Re: Learning functions; roots of the quadratic; two return values jacobnavia <jacob@jacob.remcomp.fr> - 2015-10-03 23:08 +0200
Re: Learning functions; roots of the quadratic; two return values Richard Heathfield <rjh@cpax.org.uk> - 2015-10-03 22:52 +0100
Re: Learning functions; roots of the quadratic; two return values Rosario19 <Ros@invalid.invalid> - 2015-10-04 20:46 +0200
Re: Learning functions; roots of the quadratic; two return values Keith Thompson <kst-u@mib.org> - 2015-10-04 15:47 -0700
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-05 03:06 +0200
Re: Learning functions; roots of the quadratic; two return values Rosario19 <Ros@invalid.invalid> - 2015-10-05 05:31 +0200
Re: Learning functions; roots of the quadratic; two return values Rosario19 <Ros@invalid.invalid> - 2015-10-05 11:58 +0200
Re: Learning functions; roots of the quadratic; two return values Rosario19 <Ros@invalid.invalid> - 2015-10-05 12:00 +0200
Re: Learning functions; roots of the quadratic; two return values Rosario19 <Ros@invalid.invalid> - 2015-10-05 12:06 +0200
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-05 12:39 +0200
Re: Learning functions; roots of the quadratic; two return values Bartc <bc@freeuk.com> - 2015-10-05 12:20 +0100
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-05 13:50 +0200
Re: Learning functions; roots of the quadratic; two return values Richard Heathfield <rjh@cpax.org.uk> - 2015-10-05 12:57 +0100
Re: Learning functions; roots of the quadratic; two return values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-05 05:40 +0000
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-05 08:30 +0200
Re: Learning functions; roots of the quadratic; two return values Philip Lantz <prl@canterey.us> - 2015-10-05 10:03 -0700
Re: Learning functions; roots of the quadratic; two return values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-05 22:25 +0000
Re: Learning functions; roots of the quadratic; two return values James Kuyper <jameskuyper@verizon.net> - 2015-10-05 19:26 -0400
Re: Learning functions; roots of the quadratic; two return values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-06 03:44 +0000
Re: Learning functions; roots of the quadratic; two return values James Kuyper <jameskuyper@verizon.net> - 2015-10-06 10:55 -0400
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-06 23:07 +0200
Re: Learning functions; roots of the quadratic; two return values James Kuyper <jameskuyper@verizon.net> - 2015-10-06 18:35 -0400
Re: Learning functions; roots of the quadratic; two return values raltbos@xs4all.nl (Richard Bos) - 2015-10-14 11:08 +0000
Re: Learning functions; roots of the quadratic; two return values James Kuyper <jameskuyper@verizon.net> - 2015-10-14 11:11 -0400
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-14 22:22 +0200
Re: Learning functions; roots of the quadratic; two return values James Kuyper <jameskuyper@verizon.net> - 2015-10-14 17:17 -0400
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-14 23:45 +0200
Re: Learning functions; roots of the quadratic; two return values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-15 00:11 +0000
Re: Learning functions; roots of the quadratic; two return values Bartc <bc@freeuk.com> - 2015-10-15 01:37 +0100
Re: Learning functions; roots of the quadratic; two return values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-15 05:52 +0000
Re: Learning functions; roots of the quadratic; two return values James Kuyper <jameskuyper@verizon.net> - 2015-10-14 21:54 -0400
Re: Learning functions; roots of the quadratic; two return values asetofsymbols@gmail.com - 2015-10-14 22:40 -0700
Re: Learning functions; roots of the quadratic; two return values asetofsymbols@gmail.com - 2015-10-15 05:00 -0700
Re: Learning functions; roots of the quadratic; two return values supercat@casperkitty.com - 2015-10-15 11:58 -0700
Re: Learning functions; roots of the quadratic; two return values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-15 06:04 +0000
Re: Learning functions; roots of the quadratic; two return values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-06 23:18 +0000
Re: Learning functions; roots of the quadratic; two return values supercat@casperkitty.com - 2015-10-06 16:31 -0700
Re: Learning functions; roots of the quadratic; two return values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-07 00:38 +0000
Re: Learning functions; roots of the quadratic; two return values supercat@casperkitty.com - 2015-10-06 21:19 -0700
Re: Learning functions; roots of the quadratic; two return values James Kuyper <jameskuyper@verizon.net> - 2015-10-06 22:15 -0400
Re: Learning functions; roots of the quadratic; two return values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-07 08:45 +0000
Re: Learning functions; roots of the quadratic; two return values Melzzzzz <mel@zzzzz.com> - 2015-10-07 05:19 +0200
Re: Learning functions; roots of the quadratic; two return values Keith Thompson <kst-u@mib.org> - 2015-10-07 09:12 -0700
Re: Learning functions; roots of the quadratic; two return values Melzzzzz <mel@zzzzz.com> - 2015-10-08 00:53 +0200
Re: Learning functions; roots of the quadratic; two return values Keith Thompson <kst-u@mib.org> - 2015-10-07 16:23 -0700
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-06 02:16 +0200
Re: Learning functions; roots of the quadratic; two return values supercat@casperkitty.com - 2015-10-06 15:43 -0700
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-07 02:48 +0200
Re: Learning functions; roots of the quadratic; two return values Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-14 14:00 -0700
Re: Learning functions; roots of the quadratic; two return values regis <regis.barbanchon@free.fr> - 2015-10-14 23:23 +0200
Re: Learning functions; roots of the quadratic; two return values Geoff <geoff@invalid.invalid> - 2015-10-03 12:50 -0700
Re: Learning functions; roots of the quadratic; two return values Bartc <bc@freeuk.com> - 2015-10-03 21:16 +0100
Re: Learning functions; roots of the quadratic; two return values alla.rashitova@gmail.com - 2015-10-05 09:02 -0700
Re: Learning functions; roots of the quadratic; two return values Richard Heathfield <rjh@cpax.org.uk> - 2015-10-05 17:13 +0100
Re: Learning functions; roots of the quadratic; two return values Barry Schwarz <schwarzb@dqel.com> - 2015-10-03 15:37 -0700
Re: Learning functions; roots of the quadratic; two return values Rosario19 <Ros@invalid.invalid> - 2015-10-05 23:44 +0200
Re: Learning functions; roots of the quadratic; two return values Geoff <geoff@invalid.invalid> - 2015-10-05 18:37 -0700
Re: Learning functions; roots of the quadratic; two return values Barry Schwarz <schwarzb@dqel.com> - 2015-10-05 19:24 -0700
Re: Learning functions; roots of the quadratic; two return values Rosario19 <Ros@invalid.invalid> - 2015-10-06 07:36 +0200
Re: Learning functions; roots of the quadratic; two return values Rosario19 <Ros@invalid.invalid> - 2015-10-06 07:34 +0200
csiph-web