Comment by squadrick

> That's not safe. PIDs are recycled.

Yup, didn't think of that possibility, thanks for pointing it out.

> You may (should?) be able to initialize a pthread-based PTHREAD_PROCESS_SHARED + PTHREAD_MUTEX_ROBUST mutex in a shared memory region and have everything just work.

Trying this now, I'll make another post if I can get it working. Thanks for the suggestion.