Archive for category: Patterns

Broker

Broker

April 11, 2023

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The Broker Pattern structures distributed software systems that interact with remote service invocations.…

PipesAndFilter

Pipes-and-Filters

April 2, 2023

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The Pipes-and-Filters architecture pattern describes the structure of systems that process data streams. The…

Layers

Layers

March 26, 2023

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The layers pattern splits a task into horizontal layers. Each layer has a specific responsibility and…

Layers

Architectural Patterns

March 19, 2023

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Architectural patterns describe the fundamental structure of a software system and are often based on…

QualitätsmerkmaleFokusWartbarkeit EN

How can you recognise a good software architecture?

March 6, 2023

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I'm happy to present today a guest post from Alexander Eisenhuth. Alexander will write about his passion:…

IdiomsPolymorphismTemplates

Idioms for Polymorphism and Templates

March 5, 2023

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This post is unique because I have written about all the topics mentioned in this post already. Therefore,…

ClassIdioms

Covariant Return Type

February 26, 2023

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The Covariant Return Type of a member function allows an overriding member function to return a narrower…

ClassIdioms

The Iterator Protocol

February 19, 2023

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When you want to use a user-defined type in a range-based for-loop, your user-defined type has to implement…

ClassIdioms

The Null Object Pattern

February 12, 2023

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A Null Object encapsulates a do nothing behavior inside an object. It is often pretty comfortable to…

ClassIdioms

Value Objects

February 5, 2023

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A value object is a small object whose equality is based on state, but not identity. Typical value objects…

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A Lock-Free Stack: A Hazard Pointer Implementation Explained IIApril 7, 2025 - 11:11 am
In my last post, I started to explain a hazard pointer implementation: A Lock-Free Stack: A Hazard Pointer Implementation Explained I. Today, I will continue to explain the implementation. The Retire List The retire list has the public member functions isInUse, addNode, and deleteUnusedNodes. Additionally, it has the inner class RetireNode, an atomic member of […]
A Lock-Free Stack: A Hazard Pointer Implementation Explained IMarch 24, 2025 - 11:37 am
In my last post, I presented a hazard pointer implementation: A Lock-Free Stack: A Hazard Pointer Implementation. Today, I will explain the implementation. MyNode is a class template, parametrized by the type it holds: data. MyNode models the concept Node. template <typename T> concept Node = requires(T a) { {T::data}; { *a.next } -> std::same_as<T&>; […]
A Lock-Free Stack: A Hazard Pointer ImplementationMarch 10, 2025 - 11:42 am
Hazard Pointers solve all issues of the previous implementation: A Lock-Free Stack: A Simple Garbage Collector. From one Week to two Weeks You may have already noticed. I will change my blog publishing frequency from one to two weeks in the future. Writing a post using your voice is exceptionally exhausting and time-consuming. Hazard Pointers […]
A Lock-Free Stack: A Simple Garbage CollectorFebruary 24, 2025 - 11:58 am
My next lock-free stack includes a simple garbage collector. I discussed the concurrent execution of more than one topAndPush call is a Race Condition. I can safely delete a node if not more than one topAndPush call is executing concurrently. This observation is crucial for solving this memory leak issue: I store removed nodes on […]
A Lock-Free Stack: Atomic Smart PointerFebruary 17, 2025 - 11:47 am
The easiest way to solve this memory leak issue from the last post is to use a std::shared_ptr. Atomic Smart Pointer There are two ways to apply atomic operations on a std::shared_ptr: In C++11, you can use the free atomic functions on std::shared_ptr. With C++20, you can use atomic smart pointers. C++11 Using atomic operations […]
A Lock-Free Stack: A Complete ImplementationFebruary 10, 2025 - 3:01 pm
My last lock-free stack implementation was incomplete. It only supported push operations. Let’s change this. The following paragraph about sequential consistency is optional. You can easily ignore it. Sequential Consistency In my examples, I use the default memory ordering: sequential consistency. The reason is simple. Sequential consistency provides the strongest guarantees of all memory ordering […]