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read-cache-v5.c: compiler warnings

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

## tl;dr

3 messages between Aug 19, 2012 and Aug 21, 2012.

replies: 2people: 2as markdown or json

Ramsay Jones· Aug 19, 2012, 19:13 UTC · lore

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

HTH

ATB, Ramsay Jones

Thomas Gummerer· Aug 20, 2012, 08:29 UTC · re: Ramsay Jones · lore

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

On 08/19, Ramsay Jones wrote:

Show 15 quoted lines

> 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.

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.

Show 6 quoted lines

> 
> HTH
> 
> ATB,
> Ramsay Jones
>

Thomas

Ramsay Jones· Aug 21, 2012, 19:04 UTC · re: Thomas Gummerer · lore

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

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