Summary

In this chapter, you have seen how to create programs that can execute multiple threads concurrently. We also covered how to avoid data races by protecting critical sections with locks or by using atomics. You learned that C++20 comes with some useful synchronization primitives: latches, barriers, and semaphores. We then looked into execution order and the C++ memory model, which becomes important to understand when writing lock-free programs. You also discovered that immutable data structures are thread-safe. The chapter ended with some guidelines for improving performance in concurrent applications.

The next two chapters are dedicated to a completely new C++20 feature called coroutines, which allows us to write asynchronous code in a sequential style.