[Interest] Advice on random program finish crash

[Nuno Santos]

Hi Igor,

Ops… You are right, it is not static.

I have tried your suggestion but now it crashes everytime I close the app and I can’t even get a stack trace like before. If I run it on debug, it points me to assembler code. Not anything I can really point to.

Regards,

Nuno

> 
> On 07 Jan 2015, at 10:19, Igor Mironchik <igor.mironchik at gmail.com> wrote:
> 
> On Wed, 07 Jan 2015 13:01:32 +0300, Nuno Santos <nunosantos at imaginando.pt <mailto:nunosantos at imaginando.pt>> wrote:
> 
>> Yes,
>> 
>> int main(int argc, char **argv)
>> {
>>    QGuiApplication app(argc, argv);
>> 
>>    ...
>> 
>>    return app.exec();
>> }
> 
> No. Here QGuiApplication is not static. Then in your app the situation is the next: QGuiApplication destroyes before your Manager. But any QObject-derived class must be created after QApplication and destroyed before QApplication. May be this is the reason of your crash.
> 
> Make QGuiApplication static. For example:
> 
> static QSharedPointer< QApplication > application( int argc = 0, char ** argv = 0 )
> {
> 	static QSharedPointer< QApplication > app(
> 		new QApplication( argc, argv ) );
> 
> 	return app;
> }
> 
> and in main()
> 
> QSharedPointer< QApplication > app = application( argc, argv );
> 
> before any QObject...
> 
>> 
>> 
>>> On 07 Jan 2015, at 09:54, Igor Mironchik <igor.mironchik at gmail.com> wrote:
>>> 
>>> Hi, I have one question: is QApplication static too?
>>> 
>>> On Wed, 07 Jan 2015 12:32:21 +0300, Nuno Santos <nunosantos at imaginando.pt>
>>> wrote:
>>> 
>>>> Hi,
>>>> 
>>>> I’m having a problem with a random crash that not always happens. I
>>>> would like to have your advice on how to find the origin of it.
>>>> 
>>>> This crash always happens on program exit and the stack trace is the
>>>> following:
>>>> 
>>>> Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
>>>> 0   org.qt-project.QtCore         	0x0000000109a03549
>>>> QMutexPrivate::allocate() + 105
>>>> 1   org.qt-project.QtCore         	0x0000000109a02d1c
>>>> QBasicMutex::lockInternal(int) + 92
>>>> 2   org.qt-project.QtCore         	0x0000000109a02c64 QMutex::lock() + 52
>>>> 3   org.qt-project.QtCore         	0x0000000109a0b6fd
>>>> QWaitCondition::wait(QMutex*, unsigned long) + 173
>>>> 4   org.qt-project.QtCore         	0x0000000109a0aeae
>>>> QThread::wait(unsigned long) + 110
>>>> 5   org.qt-project.QtNetwork      	0x000000010a4870da
>>>> QNetworkAccessManagerPrivate::~QNetworkAccessManagerPrivate() + 58
>>>> 6   org.qt-project.QtNetwork      	0x000000010a48722e
>>>> QNetworkAccessManagerPrivate::~QNetworkAccessManagerPrivate() + 14
>>>> 7   org.qt-project.QtCore         	0x0000000109c3e7c7
>>>> QObject::~QObject() + 1879
>>>> 8   org.qt-project.QtNetwork      	0x000000010a483c16
>>>> QNetworkAccessManager::~QNetworkAccessManager() + 262
>>>> 
>>>> The only particularity of this QNetworkAccessManager is the fact that it
>>>> is instantiated on a class that is a singleton:
>>>> 
>>>> class Manager : public QObject
>>>> {
>>>> public:
>>>> 
>>>> 	static Manager* sharedManager();
>>>> 
>>>> 	...
>>>> 
>>>> 	QNetworkAccessManager* networkAccessManager();
>>>> 
>>>> 	...
>>>> 
>>>> protected:
>>>> 
>>>> 	Manager();
>>>> 	~Manager();
>>>> 
>>>> 	...
>>>> 	
>>>> 	QNetworkAccessManager _networkAccessManager;
>>>> };
>>>> 
>>>> 
>>>> Manager* Manager::sharedManager()
>>>> {
>>>> 	QMutexLocker lock(&managerMutex);
>>>> 	static Manager manager;
>>>> 	return &manager;
>>>> }
>>>> 
>>>> Manager::Manager() :
>>>> 	_networkAccessManager()
>>>> {
>>>> 	...	
>>>> }
>>>> 
>>>> Manager::~Manager()
>>>> {
>>>> 	
>>>> }
>>>> 
>>>> Is there any obvious reason for this crash to happen randomly at program
>>>> termination?
>>>> 
>>>> Thanks,
>>>> 
>>>> Regards,
>>>> 
>>>> Nuno Santos
>>>> _______________________________________________
>>>> Interest mailing list
>>>> Interest at qt-project.org
>>>> http://lists.qt-project.org/mailman/listinfo/interest
>>> 
>>> 
>>> --
>>> Best Regards,
>>> Igor Mironchik.
>>> _______________________________________________
>>> Interest mailing list
>>> Interest at qt-project.org
>>> http://lists.qt-project.org/mailman/listinfo/interest
>> 
> 
> 
> -- 
> Best Regards,
> Igor Mironchik.

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