If you make your own C extensions then you certainly have to write code to be able to pickle your classes. I did it once, don’t remember why, and it wasn’t tha

If you make your own C extensions then you certainly have to write code to be able to pickle your classes. I did it once, don’t remember why, and it wasn’t that hard but I can imagine it would quickly get out of hand if you were changing class structures on a regular basis. If you were just wrapping some library with simple C++ classes or something it also probably wouldn’t be that hard to automatically generate the pickling code.