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Groups > comp.lang.c > #393183
| From | Keith Thompson <Keith.S.Thompson+u@gmail.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Regarding assignment to struct |
| Date | 2025-05-05 13:27 -0700 |
| Organization | None to speak of |
| Message-ID | <87jz6uhkgo.fsf@nosuchdomain.example.com> (permalink) |
| References | (3 earlier) <vv9hu7$3nomg$1@dont-email.me> <20250505111213.00004b55@yahoo.com> <vv9stv$2i8j$1@dont-email.me> <20250505120145.000014f8@yahoo.com> <vvame5$ppqp$1@dont-email.me> |
Andrey Tarasevich <noone@noone.net> writes:
[...]
> #include <stdio.h>
>
> struct S { int a[10]; };
>
> int main()
> {
> struct S a, b = { 0 };
> int *pa, *pb, *pc;
>
> pa = &a.a[5],
> pb = &b.a[5],
> pc = &(a = b).a[5],
> printf("%p %p %p\n", (void *) pa, (void *) pb, (void *) pc);
> }
>
> This version has no UB.
I believe it does. pc points to an element of an object with
temporary lifetime. The value of pc is then used after the object
it points to has reached the end of its lifetime. At that point,
pc has an indeterminate value.
N3096 6.2.4p2: "If a pointer value is used in an evaluation after
the object the pointer points to (or just past) reaches the end of
its lifetime, the behavior is undefined. The representation of a
pointer object becomes indeterminate when the object the pointer
points to (or just past) reaches the end of its lifetime."
--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */
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Regarding assignment to struct Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2025-05-02 18:34 +0000
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-02 13:17 -0700
Re: Regarding assignment to struct Barry Schwarz <schwarzb@delq.com> - 2025-05-02 13:35 -0700
That depends... (Was: Regarding assignment to struct) gazelle@shell.xmission.com (Kenny McCormack) - 2025-05-02 20:44 +0000
Re: That depends... (Was: Regarding assignment to struct) Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2025-05-03 01:13 +0000
Re: That depends... (Was: Regarding assignment to struct) Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-03 02:28 +0000
Re: That depends... (Was: Regarding assignment to struct) Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2025-05-03 06:17 +0200
Re: That depends... (Was: Regarding assignment to struct) Kaz Kylheku <643-408-1753@kylheku.com> - 2025-05-03 04:31 +0000
Re: That depends... (Was: Regarding assignment to struct) Kaz Kylheku <643-408-1753@kylheku.com> - 2025-05-03 05:11 +0000
Re: That depends... (Was: Regarding assignment to struct) Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2025-05-05 12:30 +0200
Re: That depends... (Was: Regarding assignment to struct) Kaz Kylheku <643-408-1753@kylheku.com> - 2025-05-05 18:47 +0000
Re: That depends... (Was: Regarding assignment to struct) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-04 11:05 -0700
Re: That depends... (Was: Regarding assignment to struct) James Kuyper <jameskuyper@alumni.caltech.edu> - 2025-05-03 00:47 -0400
Re: That depends... (Was: Regarding assignment to struct) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-04 10:59 -0700
Re: That depends... (Was: Regarding assignment to struct) Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2025-05-04 18:16 +0000
Re: Regarding assignment to struct antispam@fricas.org (Waldek Hebisch) - 2025-05-02 21:35 +0000
Re: Regarding assignment to struct Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2025-05-03 01:43 +0000
Re: Regarding assignment to struct Andrey Tarasevich <noone@noone.net> - 2025-05-03 01:14 -0700
Re: Regarding assignment to struct Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-03 22:46 +0000
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-03 17:37 -0700
Re: Regarding assignment to struct James Kuyper <jameskuyper@alumni.caltech.edu> - 2025-05-03 23:38 -0400
Re: Regarding assignment to struct gazelle@shell.xmission.com (Kenny McCormack) - 2025-05-04 09:25 +0000
Re: Regarding assignment to struct scott@slp53.sl.home (Scott Lurndal) - 2025-05-04 14:27 +0000
Re: Regarding assignment to struct David Brown <david.brown@hesbynett.no> - 2025-05-04 18:45 +0200
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-04 13:20 -0700
Re: Regarding assignment to struct scott@slp53.sl.home (Scott Lurndal) - 2025-05-05 00:41 +0000
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-04 18:42 -0700
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-05 21:57 -0700
Re: Regarding assignment to struct James Kuyper <jameskuyper@alumni.caltech.edu> - 2025-05-04 21:08 -0400
Re: Regarding assignment to struct Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-03 22:47 +0000
Re: Regarding assignment to struct Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-03 22:46 +0000
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-04 06:48 -0700
Re: Regarding assignment to struct Andrey Tarasevich <noone@noone.net> - 2025-05-04 22:22 -0700
Re: Regarding assignment to struct Michael S <already5chosen@yahoo.com> - 2025-05-05 11:12 +0300
Re: Regarding assignment to struct Andrey Tarasevich <noone@noone.net> - 2025-05-05 01:29 -0700
Re: Regarding assignment to struct Michael S <already5chosen@yahoo.com> - 2025-05-05 12:01 +0300
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-05 07:14 -0700
Re: Regarding assignment to struct Andrey Tarasevich <noone@noone.net> - 2025-05-05 08:45 -0700
Re: Regarding assignment to struct Michael S <already5chosen@yahoo.com> - 2025-05-05 20:20 +0300
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-05 22:26 -0700
Re: Regarding assignment to struct Andrey Tarasevich <noone@noone.net> - 2025-05-29 05:11 -0700
Re: Regarding assignment to struct James Kuyper <jameskuyper@alumni.caltech.edu> - 2025-05-29 12:57 -0400
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-05 13:27 -0700
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-05 17:04 -0700
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-05 17:53 -0700
Re: Regarding assignment to struct David Brown <david.brown@hesbynett.no> - 2025-05-06 11:35 +0200
Re: Regarding assignment to struct Andrey Tarasevich <noone@noone.net> - 2025-05-29 05:19 -0700
Re: Regarding assignment to struct David Brown <david.brown@hesbynett.no> - 2025-05-29 21:05 +0200
Re: Regarding assignment to struct antispam@fricas.org (Waldek Hebisch) - 2025-05-06 17:36 +0000
Re: Regarding assignment to struct David Brown <david.brown@hesbynett.no> - 2025-05-06 20:46 +0200
Re: Regarding assignment to struct scott@slp53.sl.home (Scott Lurndal) - 2025-05-06 19:22 +0000
Re: Regarding assignment to struct David Brown <david.brown@hesbynett.no> - 2025-05-07 09:37 +0200
Re: Regarding assignment to struct Andrey Tarasevich <noone@noone.net> - 2025-05-29 05:49 -0700
Re: Regarding assignment to struct Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2025-05-29 16:33 +0200
Re: Regarding assignment to struct David Brown <david.brown@hesbynett.no> - 2025-05-29 21:20 +0200
Re: Regarding assignment to struct scott@slp53.sl.home (Scott Lurndal) - 2025-05-29 21:15 +0000
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-29 14:54 -0700
Re: Regarding assignment to struct scott@slp53.sl.home (Scott Lurndal) - 2025-05-30 14:29 +0000
Re: Regarding assignment to struct David Brown <david.brown@hesbynett.no> - 2025-05-30 10:50 +0200
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-06 13:06 -0700
Re: Regarding assignment to struct Andrey Tarasevich <noone@noone.net> - 2025-05-29 05:21 -0700
Re: Regarding assignment to struct Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2025-05-29 16:43 +0200
Re: Regarding assignment to struct Andrey Tarasevich <noone@noone.net> - 2025-05-29 05:14 -0700
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-29 13:56 -0700
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-05 07:03 -0700
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-05 01:26 -0700
Re: Regarding assignment to struct Andrey Tarasevich <noone@noone.net> - 2025-05-05 10:14 -0700
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-08 12:45 -0700
Re: Regarding assignment to struct David Brown <david.brown@hesbynett.no> - 2025-05-08 22:20 +0200
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-05 01:34 -0700
Re: Regarding assignment to struct Michael S <already5chosen@yahoo.com> - 2025-05-05 12:03 +0300
Re: Regarding assignment to struct gazelle@shell.xmission.com (Kenny McCormack) - 2025-05-05 11:30 +0000
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-05 13:32 -0700
Re: Regarding assignment to struct Kaz Kylheku <643-408-1753@kylheku.com> - 2025-05-05 21:10 +0000
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-05 22:57 -0700
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-05 22:40 -0700
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-05 06:34 -0700
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-05 13:43 -0700
Re: Regarding assignment to struct Nick Bowler <nbowler@draconx.ca> - 2025-05-06 19:06 +0000
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-06 13:21 -0700
Re: Regarding assignment to struct Nick Bowler <nbowler@draconx.ca> - 2025-05-07 19:09 +0000
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-07 14:23 -0700
Re: Regarding assignment to struct Nick Bowler <nbowler@draconx.ca> - 2025-05-08 12:58 +0000
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-07 21:17 -0700
Re: Regarding assignment to struct Andrey Tarasevich <noone@noone.net> - 2025-05-29 05:36 -0700
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-29 14:36 -0700
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-05 07:56 -0700
Re: Regarding assignment to struct David Brown <david.brown@hesbynett.no> - 2025-05-05 20:00 +0200
Re: Regarding assignment to struct NotAorB <atod101101@gmail.com> - 2025-05-12 16:38 -0400
Re: Regarding assignment to struct David Brown <david.brown@hesbynett.no> - 2025-05-03 11:46 +0200
Re: Regarding assignment to struct Muttley@dastardlyhq.com - 2025-05-05 08:50 +0000
Re: Regarding assignment to struct David Brown <david.brown@hesbynett.no> - 2025-05-05 13:34 +0200
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-05 13:53 -0700
Re: Regarding assignment to struct Muttley@DastardlyHQ.org - 2025-05-06 07:16 +0000
Re: Regarding assignment to struct David Brown <david.brown@hesbynett.no> - 2025-05-06 11:46 +0200
Re: Regarding assignment to struct Muttley@DastardlyHQ.org - 2025-05-06 10:18 +0000
Re: Regarding assignment to struct Michael S <already5chosen@yahoo.com> - 2025-05-06 16:34 +0300
Re: Regarding assignment to struct Richard Damon <richard@damon-family.org> - 2025-05-03 21:42 -0400
Re: Regarding assignment to struct Michael S <already5chosen@yahoo.com> - 2025-05-04 11:01 +0300
Re: Regarding assignment to struct Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-04 08:34 +0000
Re: Regarding assignment to struct David Brown <david.brown@hesbynett.no> - 2025-05-04 14:06 +0200
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-05 21:25 -0700
Re: Regarding assignment to struct Rosario19 <Ros@invalid.invalid> - 2025-05-12 11:23 +0200
Re: Regarding assignment to struct Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-05-04 07:49 -0700
Re: Regarding assignment to struct Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-04 14:09 -0700
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