[Qt-interest] Delete QObjects which are moved to different thread

[Wilhelm]

Am 26.10.2011 09:37, schrieb Giuseppe D'Angelo:
> On 26 October 2011 09:34, Giuseppe D'Angelo<dangelog at gmail.com>  wrote:
>> On 26 October 2011 09:27, Wilhelm<wilhelm.meier at fh-kl.de>  wrote:
>>> Hi,
>>>
>>> if I move a QObject to a different QThread and then destroy this object
>>> deferred, the dtor is called by this thread, if it is running: ok.
>>>
>>> But if the other thread is not running, I can't use deferred deletion
>>> since there is no running event loop.
>>> Trying to delete the object from the main thread via delete operator,
>>> the dtor ist called from a different thread than the main thread: I
>>> assume the QObject-dtor detects that the object belongs to a different
>>> thread and if that is not running it starts a new thread to execute the
>>> dtor. Right?
>>
>> Wrong.
>
> Sorry -- I hit the "send" button instead of the "save" button. :)
>
> Still, it's wrong. The object gets deleted from the main thread, and
> that's something you shouldn't do (QObjects are reentrant and not
> thread safe -- they're supposed to be accessed only from the thread
> they're living in).

see the attached minimal example producing the following output:

Test::Test(QObject*) QThread(0x25231a0)
Worker::Worker(QObject*) QThread(0x25231a0)
void Test::test() QThread(0x25231a0)
virtual Worker::~Worker() QThread(0x2534390)

if the thread isn't started!

>
> Why did you move the object in the first place if you don't have a
> running thread with a running event loop? Or, if that thread has
> finished, why didn't you clean up the objects living in it?

it was just curiousity!

>
> Cheers,
> --
> Giuseppe D'Angelo
> _______________________________________________
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> Qt-interest at qt.nokia.com
> http://lists.qt.nokia.com/mailman/listinfo/qt-interest


-- 
Wilhelm

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