Re: read-cache-v5.c: compiler warnings

From: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Date: Aug 21, 2012, 19:04 UTC
Message-ID: <5033DBC9.7010707@ramsay1.demon.co.uk>
In-Reply-To: <20120820082854.GA10909@tommy-fedora>

Thomas Gummerer wrote:

Show 20 quoted lines

> On 08/19, Ramsay Jones wrote:
>> Hi Thomas,
>>
>> Just an FYI; two out of the three gcc compilers I use (Linux, cygwin
>> but not MingW), issue the following warnings:
>>
>>         CC read-cache-v5.o
>>     read-cache-v5.c: In function `write_index_v5':
>>     read-cache-v5.c:1011: warning: 'dir' might be used uninitialized in this function
>>     read-cache-v5.c:1012: warning: 'search' might be used uninitialized in this function
>>     read-cache-v5.c:1012: warning: 'found' might be used uninitialized in this function
>>
>> [commit d2537158 ("Write index-v5", 16-08-2012)]
>>
>> Normally I would take a look and offer a patch, but I haven't found time
>> to do so in the last 10 days. So, I'm just giving you a heads up ... ;-P
> 
> Thanks for noticing.  This warnings only seem to be issued by older
> versions of gcc, which is probably why two compilers give the warnings
> while one doesn't.

You would hope that was true, but I would not bet on it! I've seen these types of warnings (which rely heavily on analysis performed primarily for optimisation) come and go several times in gcc.

> The variables can never be uninitialized, because they are guarded by
> ifs and older versions don't seem to recognize that.  I'll fix them
> in a re-roll though (or a separate patch if that's preferred), just
> waiting for some feedback for v4 of my series.

Thanks!

ATB, Ramsay Jones