* Warnings building 2.4.22rc2 with gcc 3.3
@ 2003-08-11 8:54 Alex Davis
2003-08-11 15:50 ` Willy Tarreau
0 siblings, 1 reply; 4+ messages in thread
From: Alex Davis @ 2003-08-11 8:54 UTC (permalink / raw)
To: linux-kernel
When I build 2.4.22rc2 with gcc 3.3, I get the following warnings
vt.c:166: warning: comparison is always false due to limited range of data type
vt.c:283: warning: comparison is always false due to limited range of data type
keyboard.c:644: warning: comparison is always true due to limited range of data type
It seems an unsigned char is being compared with 256, which always returns false.
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Warnings building 2.4.22rc2 with gcc 3.3
2003-08-11 8:54 Warnings building 2.4.22rc2 with gcc 3.3 Alex Davis
@ 2003-08-11 15:50 ` Willy Tarreau
2003-08-11 16:59 ` Luiz Capitulino
0 siblings, 1 reply; 4+ messages in thread
From: Willy Tarreau @ 2003-08-11 15:50 UTC (permalink / raw)
To: Alex Davis; +Cc: linux-kernel
On Mon, Aug 11, 2003 at 01:54:53AM -0700, Alex Davis wrote:
> When I build 2.4.22rc2 with gcc 3.3, I get the following warnings
>
>
> vt.c:166: warning: comparison is always false due to limited range of data type
> vt.c:283: warning: comparison is always false due to limited range of data type
> keyboard.c:644: warning: comparison is always true due to limited range of data type
>
> It seems an unsigned char is being compared with 256, which always returns false.
For keyboard.c, the test is :
if (value < SIZE(func_table)) {
so it's reassuring that any value is contained in the table. We could hide
the warning with a cast of value to (int).
for vt.c, it's the same concept, some bounds are enforced on some values, and
in the event they would be violated, -EINVAL would be returned. So the check,
even if useless here, has some sense. Here again, a cast could hide the
warnings, but may generate useless code.
Cheers,
Willy
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Warnings building 2.4.22rc2 with gcc 3.3
2003-08-11 15:50 ` Willy Tarreau
@ 2003-08-11 16:59 ` Luiz Capitulino
0 siblings, 0 replies; 4+ messages in thread
From: Luiz Capitulino @ 2003-08-11 16:59 UTC (permalink / raw)
To: Willy Tarreau; +Cc: Alex Davis, linux-kernel
Willy,
Em Seg, 2003-08-11 às 12:50, Willy Tarreau escreveu:
> On Mon, Aug 11, 2003 at 01:54:53AM -0700, Alex Davis wrote:
> > When I build 2.4.22rc2 with gcc 3.3, I get the following warnings
> >
> >
> > vt.c:166: warning: comparison is always false due to limited range of data type
> > vt.c:283: warning: comparison is always false due to limited range of data type
> > keyboard.c:644: warning: comparison is always true due to limited range of data type
> >
> > It seems an unsigned char is being compared with 256, which always returns false.
>
> For keyboard.c, the test is :
>
> if (value < SIZE(func_table)) {
>
> so it's reassuring that any value is contained in the table. We could hide
> the warning with a cast of value to (int).
I'm getting it in 2.6.0-test3(-mm1) too. The problem (I think) is
that the ''if'' is aways true because ''value'' never will be > than
''SIZE(func_table)''.
The cast does not solve the problem, because ''value'' have just
8 bits (unsigned char) used, in other words, with the cast
the ''if'' will continue to be true.
--
Luiz Fernando N. Capitulino
<lcapitulino@prefeitura.sp.gov.br>
<http://www.telecentros.sp.gov.br>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Warnings building 2.4.22rc2 with gcc 3.3
@ 2003-08-11 15:26 Alex Davis
0 siblings, 0 replies; 4+ messages in thread
From: Alex Davis @ 2003-08-11 15:26 UTC (permalink / raw)
To: linux-kernel
Any ideas?
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2003-08-11 8:54 Warnings building 2.4.22rc2 with gcc 3.3 Alex Davis
2003-08-11 15:50 ` Willy Tarreau
2003-08-11 16:59 ` Luiz Capitulino
2003-08-11 15:26 Alex Davis
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