IIRC there was at least one language that implemented CCRs natively in its syntax. I want to say it's Ada but I could be wrong. If anyone else knows about it pl

IIRC there was at least one language that implemented CCRs natively in its syntax. I want to say it's Ada but I could be wrong. If anyone else knows about it please correct me. To understand it better here's the solution to the producer/consumer problem (from wikipedia), using mutexes and semaphores: mtx buffer_mutex; sem fillCount = 0; sem emptyCount = BUFFER_SIZE; procedure producer() { while (true) { item = produceItem(); down(emptyCount); down(buffer_mutex); putItemIntoBuffer(item); up(buffer_mutex); up(fillCount); } } procedure consumer() { while (true) { down(fillCount); down(buffer_mutex); item = removeItemFromBuffer(); up(buffer_mutex); up(emptyCount); consumeItem(item); } } and the same problem solved using CCRs: int avl = 0; procedure producer() { while (true) { item = produceItem(); region R when (avl < BUFFER_SIZE) { putItemIntoBuffer(item); avl++; } } } procedure consumer() { while (true) { region R when (avl > 0) { item = removeItemFromBuffer(); avl--; } consumeItem(item); } } The most important thing about CCRs is that they are supposed to guarantee fairness, along with mutual exclusion. A well-designed solution uses two binary semaphore queues to achieve this. If anyone wants to see what an implementation looks like here's a small C library I wrote a while ago, to use for some of my own personal projects, and to solve some homework for Uni https://github.com/Gikoskos/libccr https://github.com/Gikoskos/libccr