Hey everyone! I'm dealing with a strange issue while trying to fuse macOS Bluetooth code written in Objective-C with my Python bindings, and I've been stuck for a week now. Here's the scoop: I've created a C interface that abstracts Bluetooth operations for both Windows and macOS. On macOS, I'm using Objective-C with delegates to work with Apple's Bluetooth stack. I expose this C interface to Python through ctypes and build a .whl file for easier installation of the C library. This setup goes smoothly on Windows, but I'm hitting a wall on macOS. Here's the problem: the Objective-C delegate methods are never triggered. I suspect this is due to the fact that Objective-C needs a run loop to be active for delegates to work properly. When it was part of a full macOS app, it functioned flawlessly, but now that it's invoked through the C interface from Python, the delegates are silent. I've attempted a few things, like running `[[NSRunLoop currentRunLoop] run]` in different threads, creating my own run loop, and even using Python threads with ctypes to spawn a native loop, but none of these solutions seem to help. So, I'm reaching out: How can I effectively start and manage the Objective-C run loop when my C/Objective-C code is being called from Python via ctypes? Is there a reliable pattern or workaround for this cross-language integration? Any tips or insights would be greatly appreciated!
1 Answer
I think the key here is how you're managing the run loop from Python. Since Objective-C requires an active run loop for the delegates to work, you'll want to ensure that the run loop is running in the main thread of your application. A common approach is to create a separate thread in Python dedicated to the Objective-C run loop. You can use `NSThread` in your C code to run the loop on its own thread. Just make sure to ensure thread safety since you'd be dealing with callbacks from Objective-C in a different thread. Here’s a simplified version of how you can set this up: use a dedicated thread that calls `[[NSRunLoop currentRunLoop] run]`, and then from Python, invoke your C interface—all while ensuring that the delegates can call back properly.
That's a good point about thread safety! Just make sure that any data shared between Python and Objective-C is protected. You might also want to consider using GCD for managing your threads as it can simplify some of this process.