Re: ObjectAlloc crashes my app
Re: ObjectAlloc crashes my app
- Subject: Re: ObjectAlloc crashes my app
- From: Matt Neuburg <email@hidden>
- Date: Tue, 10 Jul 2007 08:46:58 -0700
- Thread-topic: ObjectAlloc crashes my app
On or about 7/10/07 8:25 AM, thus spake "Martin Redington"
<email@hidden>:
> You might also check what options you're running with ObjectAlloc.
>
> WhackedTV dies for me with a SIGBUS (10), when I run it from
> ObjectAlloc with the "Identify general allocations by library" option
> checked, and add a video track, but seems to be ok otherwise.
>
> On 7/10/07, j o a r <email@hidden> wrote:
>>
>> On 10 jul 2007, at 01.38, Matt Neuburg wrote:
>>
>>> The problem seems to have to do with QTKit and loading a QTMovie. If I
>>> comment out the code that loads the QTMovie, the problem vanishes.
>>> Is there
>>> some known bad interaction between ObjectAlloc and QTKit?
>>
>>
>> If you can reproduce such a problem, and in particular if you can
>> reduce it to a sample project that exhibits the problem, please
>> remember to file a bug report.
Well, I now believe that this was just my programming bug, and that the role
of ObjectAlloc in the mix was diagnostic rather than causational. In
particular, I think I had a pointer whose value was unpredictable. It just
happened that in all my normal testing, my assumption that this pointer's
value was either nil or a valid NSError was working. Therefore, I was
unaware that this assumption might be false. ObjectAlloc altered things to
the point where that assumption was *exposed* as false: the pointer was now
pointing at junk, causing the crash.
So, in conclusion, my post was a red herring and just noise, which is
embarrassing and for which I apologize. On the other hand, although I'm not
glad that I posted wrongly, I'm very glad that this *happened*, because if I
hadn't discovered the bug by "prodding" my app with ObjectAlloc, I would
have discovered it only when some user reported a crash, which would have
been a lot *more* embarrassing! m.
--
matt neuburg, phd = email@hidden, http://www.tidbits.com/matt/
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