From: wempwer@gmail.com
To: "Jędrzej Dudkiewicz" <jedrzej.dudkiewicz@gmail.com>
Cc: gcc-help <gcc-help@gcc.gnu.org>
Subject: Re: how to make gcc warn about arithmetic signed overflow
Date: Sat, 21 Sep 2013 21:07:00 -0000 [thread overview]
Message-ID: <20130921210740.GJ3086@a.lan> (raw)
In-Reply-To: <CABJqhQP-3HQVRMa9a94poJ1Ji+8RHa_5tmf2hUbzGKGNUeo6Pg@mail.gmail.com>
On Sat, Sep 21, 2013 at 10:52:22PM +0200, JÄdrzej Dudkiewicz wrote:
> >> > I think I can but it may cause an undefined behavior:
> >>
> >> Note, that Jonathan wrote "in a valid program". Your program is not
> >> valid, as it contains undefined behaviour - you change const int via
> >> pointer to non-const int.
> >
> > Is p pointer in my code a pointer to non-const int? It points to bc
> > int memory address and bc is constant. Does C language bind constness
> > to an indentifier instead of memory address?
>
> Yes. I don't know about your version of gcc, but with 4.8.1 I get:
>
> [jd@megalodon ~]$ cat x.c
> int main() {
> const int i = 10;
> int* pc = &i;
> *pc = 1;
> return *pc;
> }
>
> [jd@megalodon ~]$ gcc x.c -o x
> x.c: In function âmainâ:
> x.c:3:12: warning: initialization discards âconstâ qualifier from
> pointer target type [enabled by default]
> int* pc = &i;
>
> Which means that pc doesn't inherit constness of pointed ...memory?
> value? I'm not sure how to call it.
Oh, my gcc shows me the same warning. Thank you for clarification.
--
<wempwer@gmail.com>
next prev parent reply other threads:[~2013-09-21 21:07 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-21 16:45 wempwer
2013-09-21 17:24 ` Jonathan Wakely
2013-09-21 17:41 ` wempwer
2013-09-21 18:30 ` Jonathan Wakely
2013-09-21 18:50 ` wempwer
2013-09-21 19:55 ` Jędrzej Dudkiewicz
2013-09-21 20:16 ` wempwer
2013-09-21 20:52 ` Jędrzej Dudkiewicz
2013-09-21 21:07 ` wempwer [this message]
2013-09-23 4:04 ` James K. Lowden
2013-09-23 7:55 ` Jonathan Wakely
2013-09-23 15:47 ` James K. Lowden
2013-09-23 21:50 ` Jonathan Wakely
2013-09-23 22:44 ` James K. Lowden
2013-09-23 23:20 ` Jonathan Wakely
2013-09-23 19:38 ` Dave Allured - NOAA Affiliate
2013-09-23 19:43 ` Oleg Endo
2013-09-23 20:37 ` Dave Allured - NOAA Affiliate
2013-09-23 19:48 ` Andrew Haley
2013-09-23 22:00 ` James K. Lowden
2013-09-24 17:48 ` Andrew Haley
2013-09-26 2:30 ` James K. Lowden
2013-09-26 8:29 ` Vincent Lefevre
2013-09-26 14:49 ` Andrew Haley
2013-09-26 17:03 ` Vincent Lefevre
2013-09-26 18:19 ` Andrew Haley
2013-09-27 7:58 ` Vincent Lefevre
2013-09-27 8:23 ` Andrew Haley
2013-09-27 9:28 ` Vincent Lefevre
2013-09-27 9:43 ` Andrew Haley
2013-09-26 17:41 ` Andrew Haley
2013-09-24 7:42 ` Brian Drummond
2013-09-21 17:53 ` Marc Glisse
2013-09-21 18:09 ` wempwer
2013-09-21 18:27 ` Jonathan Wakely
2013-09-21 19:32 ` wempwer
2013-09-22 15:52 ` Jonathan Wakely
2013-09-23 13:04 ` David Brown
2013-09-21 17:36 ` Brian Drummond
2013-09-21 17:45 ` wempwer
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