SCXML and QScxmlCppDataModel cause a segmentation fault

[bouchebeu]

Hello everyone,

I'm using the QScxmlStateMachine and wanted to use the QScxmlCppDataModel.
I copied the "mediaplayer-qml-cppdatamodel" example and executed it without any problem.

Since I'm not using QML, i replaced the main function with the following:

int main(int argc, char *argv[])
{
	QCoreApplication	a(argc, argv);
	QScxmlStateMachine*	machine	= new MediaPlayerStateMachine() ;
 
	machine->start();
 
	return a.exec();
}

int main(int argc, char *argv[])
{
	QCoreApplication	a(argc, argv);
	QScxmlStateMachine*	machine	= new MediaPlayerStateMachine() ;

	machine->start();

	return a.exec();
}

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Unfortunately, I get a segmentation fault that I remove when I comment the line (in my .scxml) datamodel="cplusplus:TheDataModel:thedatamodel.h".

I also tried to simply add the QScxmlStateMachine instantiation and starting inside the original main function but it still fails.

int main(int argc, char *argv[])
{
	QGuiApplication app(argc, argv);
 
	qmlRegisterType<TheDataModel>("MediaPlayerDataModel", 1, 0, "MediaPlayerDataModel");
	qmlRegisterType<MediaPlayerStateMachine>("MediaPlayerStateMachine", 1, 0, "MediaPlayerStateMachine");
 
	QQmlApplicationEngine engine;
	engine.load(QUrl(QStringLiteral("qrc:///mediaplayer-qml-cppdatamodel.qml")));
 
	QScxmlStateMachine*	machine	= new MediaPlayerStateMachine() ;
	machine->start();
 
	return app.exec();
}

int main(int argc, char *argv[])
{
	QGuiApplication app(argc, argv);

	qmlRegisterType<TheDataModel>("MediaPlayerDataModel", 1, 0, "MediaPlayerDataModel");
	qmlRegisterType<MediaPlayerStateMachine>("MediaPlayerStateMachine", 1, 0, "MediaPlayerStateMachine");

	QQmlApplicationEngine engine;
	engine.load(QUrl(QStringLiteral("qrc:///mediaplayer-qml-cppdatamodel.qml")));

	QScxmlStateMachine*	machine	= new MediaPlayerStateMachine() ;
	machine->start();

	return app.exec();
}

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Launching in debug gives only the line where the error occurs which is return app.exec();

Does it ring a bell to anyone?


Thanks.

Qt5.7.1 on linux 64

[bouchebeu]

Ok, found where the issue is.

I forgot to set the data model; in QML example:

Mediaplayer {
MediaPlayerDataModel {
id: model
}

stateMachine: MediaPlayerStateMachine {
onDataModelChanged: start()
dataModel: model
}
}

So, in C++, I added the 2 lines for the data model:

QScxmlStateMachine* machine = new MediaPlayerStateMachine() ;
TheDataModel* dataModel = new TheDataModel();

machine->setDataModel(dataModel);
machine->start();

Hope it helps some of you.

Have great vacation everyone.