It's different and very old story. Protothreads are classic now: https://dunkels.com/adam/pt/index.html https://dunkels.com/adam/pt/index.html Contiki OS is a

It's different and very old story. Protothreads are classic now: https://dunkels.com/adam/pt/index.html https://dunkels.com/adam/pt/index.html Contiki OS is also a piece of embedded development classic: https://en.wikipedia.org/wiki/Contiki https://en.wikipedia.org/wiki/Contiki In general, it's more about syntax than semantics. Semantics is generally difficult and rarely changes.