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Groups > comp.unix.programmer > #1090
| From | Nobody <nobody@nowhere.com> |
|---|---|
| Subject | Re: C Code "sanity checking" tools |
| Date | 2011-08-09 00:59 +0100 |
| Message-Id | <pan.2011.08.08.23.59.36.778000@nowhere.com> |
| Newsgroups | comp.unix.programmer |
| References | <4e3fc1c6$0$940$c3e8da3$9f400e27@news.astraweb.com> <pan.2011.08.08.13.01.31.817000@nowhere.com> <yw1xsjpct3p7.fsf@unicorn.mansr.com> |
| Organization | Zen Internet |
On Mon, 08 Aug 2011 14:47:48 +0100, Måns Rullgård wrote:
>> In general, "gcc -O -Wall ..." will warn about using uninitialised
>> variables. It won't work in the specific case above because gcc doesn't
>> know that the printf() call will access the elements of mystring.
>
> Actually, many compilers, gcc included, parse printf format strings and
> verify the arguments are compatible.
That isn't relevant to the part you quoted (it /is/ relevant to the
issue of printf() being variadic, which I mentioned at the end).
Type information alone isn't sufficient to accurately determine behaviour
(although it might be a useful heuristic). In spite of knowing the
argument types, gcc won't complain about this either:
#include <stdio.h>
#include <string.h>
int main(void)
{
char mystring[5];
printf("Length:%d\n",strlen(mystring));
return 0;
}
A heuristic-based analyser might infer that passing a "const" pointer to
uninitialised data is probably an error, although it's not certain.
Ultimately, you can't know for sure without knowing the workings of the
library function.
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C Code "sanity checking" tools Martin Crouch <spamspamspam@spaml.com> - 2011-08-08 12:00 +0100
Re: C Code "sanity checking" tools Richard Kettlewell <rjk@greenend.org.uk> - 2011-08-08 12:09 +0100
Re: C Code "sanity checking" tools Fritz Wuehler <fritz@spamexpire-201108.rodent.frell.theremailer.net> - 2011-08-09 08:50 +0200
Re: C Code "sanity checking" tools Måns Rullgård <mans@mansr.com> - 2011-08-09 10:55 +0100
Re: C Code "sanity checking" tools Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-08-09 14:15 +0100
Re: C Code "sanity checking" tools Nomen Nescio <nobody@dizum.com> - 2011-08-10 01:58 +0200
Re: C Code "sanity checking" tools Nomen Nescio <nobody@dizum.com> - 2011-08-10 12:29 +0200
Re: C Code "sanity checking" tools Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-09 14:17 +0100
Re: C Code "sanity checking" tools Keith Thompson <kst-u@mib.org> - 2011-08-09 09:17 -0700
Re: C Code "sanity checking" tools Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-09 17:36 +0100
Re: C Code "sanity checking" tools Keith Thompson <kst-u@mib.org> - 2011-08-09 12:19 -0700
Re: C Code "sanity checking" tools Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-09 20:36 +0100
Re: C Code "sanity checking" tools Michael Press <rubrum@pacbell.net> - 2011-08-09 19:24 -0700
Re: C Code "sanity checking" tools Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-10 10:27 +0100
Re: C Code "sanity checking" tools Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-10 14:01 +0100
Re: C Code "sanity checking" tools "io_x" <a@b.c.invalid> - 2011-08-13 09:42 +0200
Re: C Code "sanity checking" tools Keith Thompson <kst-u@mib.org> - 2011-08-13 16:04 -0700
Re: C Code "sanity checking" tools Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-14 19:46 +0100
Re: C Code "sanity checking" tools Ian Collins <ian-news@hotmail.com> - 2011-08-08 23:12 +1200
Re: C Code "sanity checking" tools Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-08-08 15:35 +0100
Re: C Code "sanity checking" tools Martin Crouch <spamspamspam@spaml.com> - 2011-08-08 16:05 +0100
Re: C Code "sanity checking" tools Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-08-08 22:57 +0100
Re: C Code "sanity checking" tools Måns Rullgård <mans@mansr.com> - 2011-08-08 23:32 +0100
Re: C Code "sanity checking" tools Ian Collins <ian-news@hotmail.com> - 2011-08-09 08:03 +1200
Re: C Code "sanity checking" tools Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-08-08 22:51 +0100
Re: C Code "sanity checking" tools Ian Collins <ian-news@hotmail.com> - 2011-08-09 10:01 +1200
Re: C Code "sanity checking" tools jt@toerring.de (Jens Thoms Toerring) - 2011-08-08 22:06 +0000
Re: C Code "sanity checking" tools Ian Collins <ian-news@hotmail.com> - 2011-08-09 10:18 +1200
Re: C Code "sanity checking" tools jt@toerring.de (Jens Thoms Toerring) - 2011-08-08 23:25 +0000
Re: C Code "sanity checking" tools Nobody <nobody@nowhere.com> - 2011-08-08 14:01 +0100
Re: C Code "sanity checking" tools Måns Rullgård <mans@mansr.com> - 2011-08-08 14:47 +0100
Re: C Code "sanity checking" tools Martin Crouch <spamspamspam@spaml.com> - 2011-08-08 16:08 +0100
Re: C Code "sanity checking" tools Marc <marc.glisse@gmail.com> - 2011-08-08 15:39 +0000
Re: C Code "sanity checking" tools William Ahern <william@wilbur.25thandClement.com> - 2011-08-08 10:20 -0700
Re: C Code "sanity checking" tools Nobody <nobody@nowhere.com> - 2011-08-09 00:59 +0100
Re: C Code "sanity checking" tools mathog <dmathog@gmail.com> - 2011-08-08 08:48 -0700
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