Re: Missing warning about uninitialized variable.

["J.C. Pizarro" <jcpiza@gmail.com>]

On 2007/11/29, eschenb@informatik.uni-frankfurt.de
<eschenb@informatik.uni-frankfurt.de> wrote:
> Aside from the fact, that you obviously forgot a #include <stdio.h>,
> of course the output is random, if the variable stays uninitialized (./foo
> $seq 1 10) has an argc of 11, doesn't it?
>
> Regards
>
> -Sven
>
> > On 2007/11/29, Mikael Vidstedt <mikael.vidstedt@bea.com> wrote:
> >> The following program may make use of an uninitialized variable (gurka):
> >>
> >> int
> >> main(int argc, char* argv[])
> >> {
> >>    int gurka;
> >>
> >>    if(argc == 10) {
> >>       gurka = 3;
> >>    }
> >>
> >>    // gurka isn't necessarily initialized here...
> >>    printf("%d\n", gurka);
> >>
> >>    return 0;
> >> }
> >>
> >> GCC 4.0 will give a warning when this program is compiled with "-O
> >> -Wall". GCC 4.1 and 4.2 do not give that warning. I haven't had the
> >> possibility to try GCC 4.3.
> >>
> >> What say ye?
> >>
> >> Thanks,
> >> Mikael
> >
> > It prints stochasticly random data too.
> >
> > gcc version 4.2.3 20071031 (prerelease)
> >
> > $ gcc -Wall -o foo foo.c
> > foo.c: In function 'main':
> > foo.c:11: warning: implicit declaration of function 'printf'
> > foo.c:11: warning: incompatible implicit declaration of built-in
> > function 'printf'
> > $ for i in $(seq 1 5); do ./foo $(seq 1 10) ; done
> > -1209020420
> > -1208291332
> > -1208422404
> > -1208803332
> > -1208823812
> > $
> >
> >    J.C.Pizarro

It can be other bug more!