C++ and concurrency

The concept of concurrency was introduced into the language in C++11, but concurrent programs were written in C++ long before that. This chapter is not meant to be an introduction to concurrency or even an introduction to concurrency in C++. This subject is well-covered in the literature (at the time of publication of this book, one of the works that are both general and up-to-date is the book C++ Concurrency in Action by Anthony Williams). Also, while concurrency is almost always used to improve performance, we will not directly address performance and optimization issues here; for that, you can refer to my book The Art of Writing Efficient Programs. We are going to focus on the problems that arise in the design of concurrent software.

There are, broadly speaking, three types of challenges we encounter when developing concurrent programs. First, how to make sure the program is correct even when multiple threads operate on the same data concurrency? Second, how...