How pass pointer from python to cpp

[Edvard]

Hello
I have problem with c function pointer wrapping. I have a c function that one of its argument is int pointer. so how can I pass pointer from python to it?

[Florian Link]

You can't. You could change the interface to take a QVector or QList of ints. The any sequence in Python will be converted to that list/vector.

[Edvard]

thanks, I want a way that each value change of variable in cpp function also applies to python. is there any way to do that?

[Florian Link]

Hm, there are various ways, but all require some work, especially if you want to be able to modify the data from both sides...

Maybe the easiest would be to use a Python array (see standard library) of the desired type. But PythonQt does not support automatic conversion, so you would need to use a PyObject pointer in your slot and use the Python C api to talk to it from C++.

Another common way is to use numpy arrays, but that will require the numpy installation and you would need to use the numpy C api to get acces to the data in the C++ slot (also with a PyObject)

And another way is to return a Python memory view and use that as a buffer for an aary or numpy array.

But all these methods require deep understanding on what you are doing...keeping the ref counts correct etc.

[Edvard]

thanks for helping