QDrag ownership

[tuli]

I implemented some custom drag+drop in the standard way. Part of the dragging code:

QDrag* drag = new QDrag(this);
drag->exec();
...

QDrag* drag = new QDrag(this);
drag->exec();
...

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Now I am wondering: Who owns the QDrag* object 'drag'?

It seems to me that I do, and I have to do delete the drag object before returning:

QDrag* drag = new QDrag(this);
drag->exec();
...
delete drag;
...

QDrag* drag = new QDrag(this);
drag->exec();
...
delete drag;
...

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However, in none of the Qt drag+drop examples this is done. They just let the pointer go out of scope and dont bother about it!

(note that the 'this' passed to the constructor is not a 'QObject* parent' but the source of the dragging.)


https://doc.qt.io/qt-5/qtwidgets-dra...idget-cpp.html


The documentation doesnt say anything special either.


Who owns it? Do I have to delete it or not?

[wysota]

I think Qt takes the ownership. You can easily verify it by subclassing QDrag and putting a qDebug() statement in the destructor to see if and when it is invoked.