[Interest] How to properly delete qApp?

[Nikos Chantziaras]

I doubt you can get out of this issue. QApplication wants to be in 
control of the main loop, and it wants to do so from the main thread.

Failing that, you'd need to integrate the host application's event loop 
into Qt's event loop, and still have a way to cal QApplication::exec() 
on the main thread. If your host application does not allow for those 
two things, I'd say there's nothing you can do.


On 16/03/16 17:42, Nuno Santos wrote:
> Nikos,
>
> Thanks for your reply.
>
> The problems is that host application hangs forever if I don’t delete it
> and crashes if I delete it. I’m in a kind of dead end.
>
> Any ideas?
>
> Thanks
>
> Nuno
>
>> On 16 Mar 2016, at 14:07, Nikos Chantziaras <realnc at gmail.com
>> <mailto:realnc at gmail.com>> wrote:
>>
>> On 16/03/16 14:01, Till Oliver Knoll wrote:
>>> I don't think you're supposed to delete qApp
>>
>> Actually you do need to delete it. Most people don't because after
>> qApp->exec() returns, the program ends anyway. But if you want to have
>> 0 leaks, you need to delete your QApplication instance.
>>
>> Usually you don't delete qApp directly, but just your instance, but
>> that's the same thing, really:
>>
>>  int main(int argc, char** argv)
>>  {
>>      QApplication app = new QApplication(/* ... */);
>>      app->exec();
>>      delete app;
>>      // or:
>>      // delete qApp;
>>      // which does the same thing.
>>  }
>>
>> In normal applications, like the above, deleting it is redundant.
>> You're exiting the process, so the environment is going to clean your
>> memory anyway. It's still a memory leak, if you're pedantic about it.
>>
>> If you're using QApplication in a plugin, deleting qApp is actually
>> mandatory, otherwise you're leaking the qApp instance when the plugin
>> unloads; no one else is going to delete it for you.
>>
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>
>
>