That's not true. I am executing everything in the same thread, ie. I only update the model. the model-view interaction is threadsafe again. Using the hook I have added - which is blocking - proves that. Also, with debug messages I can show that the readline hook is non-blocking.
AFAIK readline even hooks are blocking, as long as the hook is executing. What is probably happening is that you're executing some code in another thread than the main thread (where readline is executing), then it is possible readline triggers a new run of the hook while your code is still executing in the other thread. It's up to you to make your code safe.
Michael.