C++ High Performance

Protecting critical sections

As already mentioned, our code must not contain any data races. Unfortunately, writing code with data races is very easy. Finding the critical sections and protecting them with locks is something we constantly need to think about when writing concurrent programs in this style using threads.

C++ provides us with a std::mutex class that can be used for protecting critical sections and avoiding data races. We will demonstrate how to use a mutex with a classic example using a shared mutable counter variable updated by multiple threads.

First, we define a global mutable variable and the function incrementing the counter:

auto counter = 0; // Warning! Global mutable variable auto increment_counter(int n) { for (int ...