Implement multiple producers and consumers

The producer-consumer problem is really a set of problems. Solutions will differ if the buffer is bounded or unbounded, or if there are multiple producers, multiple consumers, or both.

Let's consider a case with multiple producers, multiple consumers, and a bounded (limited capacity) buffer. This is a common condition.

How to do it…

In this recipe, we'll look at a case with multiple producers and consumers and a bounded buffer, using a variety of techniques we've covered in this chapter:

• We'll start with some constants for convenience and reliability:

  constexpr auto delay_time{ 50ms };
  constexpr auto consumer_wait{ 100ms };
  constexpr size_t queue_limit{ 5 };
  constexpr size_t num_items{ 15 };
  constexpr size_t num_producers{ 3 };
  constexpr size_t num_consumers{ 5 };

  • delay_time is a duration object, used with sleep_for().
  • consumer_wait is a duration object, used with the consumer condition variable.
  • queue_limt...