passing opaque pointers

[bmahlbrand]

I want to accomplish something like the following:

ctx = module.init()

start(ctx)
end(ctx)

where ctx is some opaque struct pointer that python needs not be aware of (not accessing private members or anything)

using the following compiles fine, but complains when ctx is a valid pointer returned from this signature (ie passing null pointers around works fine):

context_state_struct *init(std::string path) {
    ...

thus

ctx = module.init()

crashes with the error - TypeError: Unable to convert function return value to a Python type! The signature was

I looked at nb::handle<> and nb::handle_of<> but not sure if there's something else I should be doing here.

Thanks!

[wjakob]

You need a nb::class_ declaration for context_state_struct. No need to provide a constructor/method/fields.

[bmahlbrand]

Thanks! That did it - for future travelers, I ended up with something like this:

nb::class_<context_state_struct>(m, "context_state_struct");