This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: warn/croak on "string" "string" auto-joins
On Wed, 2004-08-18 at 13:10, Chris Jefferson wrote:
> Mathieu Lacage wrote:
>
> >On Wed, 2004-08-18 at 12:12, Chris Jefferson wrote:
> >
> >
> >>Dave Korn wrote:
> >>
> >> >
> >> >>>>This would have helped early and is good practice:
> >> >>>>
> >> >>>>char *months[12] = {"Jan", "Feb", "Mar", "Apr", "May",
> >> >>
> >> >>"Jun", "Jul",
> >> >>
> >> >>>>"Aug" "Sep", "Oct", "Nov", "Dec"};
> >> >>>>
> >> >>>>--> high probability warning
> >> >>>
> >> >>>I'm not sure I understand, what does "high probability
> >> >>
> >> >>warning" mean?
> >> >>
> >> >>>I get no errors/warnings from the following:
> >> >>>
> >> >>>#include <stdio.h>
> >> >>>int main( void )
> >> >>>{
> >> >>> char *months[15] = {"Jan", "Feb", "Mar", "Apr", "May",
> >> >>
> >> >>"Jun", "Jul",
> >> >>
> >> >>>"Aug" "Sep", "Oct", "Nov", "Dec"};
> >> >>> printf("7: %s\n", months[8]);
> >> >>> return 0;
> >> >>>}
> >> >>>
> >> >>>compiled with 'gcc -Wall -pedantic -ansi', using GCC 3.3.3.
> >> >>
> >> >>Hmm, I could have sworn that a mismatch in array dimensions
> >> >>does emit a warning (too many initializers do error out "como").
> >> >>Looks like this is not the case. Sorry for bothering you :-(
> >> >
> >> >
> >> > But it has too *few* initialisers!
> >> >
> >>While not exactly what was asked for in the first place, it would seem
> >>to me this kind of problem (giving too few initalisers to a fixed length
> >>array) should definatly emit a warning.. would this be hard to do / can
> >>anyone come up with a sensible reason to give too few initalisers?
> >>
> >>
> >
> >While not a C standard guru, I think this is allowed and compatible with
> >the C99 initialization rules. Specifically, section 6.7.8, p125,
> >paragraphs 17, 19 and 10 which means that the end of your char *array is
> >initialized with null values.
> >
> >
> >
> I'm also fairly certain that it is legal.. however the purpose of
> warnings is to emit messages about things which while legal someone
> probably didn't mean to write :) and this would I think apply almost
> always in this case, and would go some way to fixing the original
> problem I think.
I am afraid that it is fairly common for certain programmers to write
this:
type array[] = {0, };
Mathieu
--
Mathieu Lacage <mathieu.lacage@sophia.inria.fr>