Re: warning: comparison is always false due to limited range of data type

[Jim Meyering]

Oskar Liljeblad <address@hidden> wrote:
> On Wednesday, June 22, 2005 at 13:47, Jim Meyering wrote:
>> >
>> > I get that warning without both -W and -Wall, I think.
>> > (gcc 3.3.6)
>>
>> I've tried with the following versions of gcc on x86_64-unknown-linux-gnu:
>>   gcc-3.3 (GCC) 3.3.6 (Debian 1:3.3.6-6)
>>   gcc-3.4 (GCC) 3.4.5 20050605 (prerelease) (Debian 3.4.4-0)
>>   gcc-4.0 (GCC) 4.0.1 20050522 (prerelease) (Debian 4.0.0-9)
>>
>> and see that warning only with -W.
>
> Strange! Is -W somehow turned on by default?
>
> $ gcc -DHAVE_CONFIG_H -I. -I. -I..     -g -O2 -c quotearg.c
> quotearg.c: In function `quotearg_n_options':
> quotearg.c:586: warning: comparison is always false due to limited range of 
> data type

No.  It was my fault.
I'd changed it to size_t, then (mistakenly) back to `int'
rather than to `unsigned int'.

Now, I too see this warning, even without any -W* or -O option:

  $ gcc-3.3 -DHAVE_CONFIG_H -I. -I.. -g -c quotearg.c
  quotearg.c: In function `quotearg_n_options':
  quotearg.c:586: warning: comparison is always false due to limited range of 
data type

Sorry about the mix-up.

I've just confirmed that this warning (from gcc/c-common.c)
does not appear to be associated with any command line option.