Hi, I'm not sure if I miss some obvious piece of documentation, but after reading https://doc.qt.io/qtforpython/shiboken2/ownership.html and also https://doc.qt.io/qtforpython/shiboken2/typesystem_arguments.html#define-ownership as well as the SampleBinding example, there are still open questions left...
One of the biggest unknowns here is the default ownership assumptions of shiboken2. It is mentioned that there are some heuristics, but unfortunately the documentation seems to be spread around the aforementioned places, and so I'm not sure if I understood everything correctly. I would like to give some examples in C++ code (assuming "A" is a wrapped C++ class which is wrapped as <object-type>) and the question is whether or not my assumptions are correct? 1. A* createA(); // default ownership of return value: target language, unless --enable-return-value-heuristic is given 2. void doSomething(A* arg); // default ownership of argument: target language 3. void doSomething(A& arg); // default ownership of argument: target language 4. const A& getReference(); // what happens here? a copy of the result is transferred to target ownership? It seems that the default is that the target language owns all objects passed around and transfer to c++ has to be made explicit in typesystem.xml? In the <define-ownership> tag documentation, for me it is completely unclear what the class attribute means? I think the default is "target", but what happens when you specify "native"? In the object ownership documentation, it is mentioned that there is the invalidate-after-use attribute, but this seems to be missing in the type system reference. The given use case is completely unclear to me and it would be good to have an example when this might be useful. All in all, the object ownership documentation could be improved greatly by giving some examples for the mentioned cases, not only in the xml domain, but also in C++ domain. Thanks for helping! - icwfm - _______________________________________________ PySide mailing list PySide@qt-project.org https://lists.qt-project.org/listinfo/pyside
