Atomics

In the last post "Dining Philosophers Problem I", Andre Adrian started his analysis of the classical dining philosophers' problem. Today, he uses atomics, mutexes, and locks.

In my last post, I introduced latches in C++20. A latch enables its threads to wait until a counter becomes zero. Additionally, to a latch, its big sibling barrier can be used more than once. Today, I write about barriers and present atomic smart pointers.

After the introduction to std::atomic_flag in my last post Synchronization with Atomics in C++20, I want to dive deeper. Today, I create a ping-pong game using condition variables, std::atomic_flag, and std::atomic<bool>. Let's play.

Sender/receiver workflows are quite common for threads. In such a workflow, the receiver is waiting for the sender's notification before it continues to work. There are various ways to implement these workflows. With C++11, you can use condition variables or promise/future pairs; with C++20, you can use atomics.

Atomics receives a few important extensions in C++20. Today, I start with the new data type std::atomic_ref.

This post concludes my overview of C++20. Today's post is about the concurrency features in the next C++ standard.

A common problem in concurrency is the so-called ABA problem. That means you read a value twice and each time it returns the same value A. Therefore you conclude that nothing changed in between. But you forgot the B.

Blocking, non-blocking, lock-free, and wait-free. Each of these terms describes a key characteristic of an algorithm when executed in a concurrent environment. So, reasoning about the runtime behavior of your program often means putting your algorithm in the right bucket. Therefore, this post is about buckets.

C++20 will have atomic smart pointers. To be exactly, we will get a std::atomic_shared_ptr and a std::atomic_weak_ptr. But why? std::shared_ptr and std::weak_ptr are already thread-safe. Sort of. Let me dive into the details.

After I've calculated in three different ways the sum of a std::vector I want to draw my conclusions.