Confusing types for callbacks

[TonyCongqianWang]

I tried to use a python function as callback and could not get it to work. After some testing I got very confused:

The signature I tested was const std::function<void(double[])> as I wanted to use a numba cfunc as a callback to modify values in my array. I was very confused, that the value of the first array member was passed instead. After digging around in the issues I found out that this was intended behaviour. Appearently const std::function<void(double*)> means that the value gets passed as a reference. This was not intuitive to me at all and I couldn't find the documentation of this behaviour.

Is there any way to actually modify an array? As I want to fill an large Array with values , I want to avoid using callbacks returning a single double. In some issues I found usage of struct types or std::vectors, but I am unsure on how to transfer this to my use case.

[TonyCongqianWang]

After thinking about it for a while I got it working as I want, though it is not pretty. I changed all pointers in my signature to size_t and used c_type.cast on the python side to convert them back to a pointer.