Instead of shared state, you use a message passing style where you pass pointers over queues. If you don't have a queue library and don't want to risk getting

Instead of shared state, you use a message passing style where you pass pointers over queues. If you don't have a queue library and don't want to risk getting the locking wrong, you can get one from pipe(2). While simultaneous writes/reads are in theory permitted to be interleaved, the implementation would have to be actively insane to interleave anywhere other than page boundaries. ...I actually did this when I was at university, for the first class that covered locking and concurrency. Amazingly enough, I didn't fail that assignment for delegating what we were supposed to be learning to the OS. The logical structure of such a program is not really that different than an Erlang program, I imagine. It just works a little better with existing C/C++ codebases, and is potentially faster in some cases. It has a completely different character than spaghetti written using threads and shared state, and can be made extremely reliable. Maybe this is why I don't get all the C++-hate? The things that make code unreliable or thread-unsafe tend to also make it hard to read and think about (even without threads), so I just find some other way that doesn't give me a headache. Interestingly code that doesn't give me a headache tends to have a strong resemblance to functional-style code, even tho actual pure functional code also tends to be mildly headache-inducing.