Archive for category: Multithreading – Memory Model

relaxed

Relaxed Semantics

July 27, 2016

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The relaxed semantics is the end of the scale. The relaxed semantic is the weakest of all memory models…

acquireOperation

Acquire-Release Fences

July 21, 2016

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Acquire and release fences guarantee similar synchronization and ordering constraints as atomics with…

FullFence

Fences are Memory Barriers

July 19, 2016

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The key idea of a std::atomic_thread_fence is to establish synchronization and ordering constraints between…

acquireReleaseWithWaiting

Acquire-Release Semantics – The Typical Misunderstanding

July 16, 2016

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A release operation synchronizes-with an acquire operation on the same atomic variable. So we can easily…

trans

Transitivity of the Acquire-Release Semantic

July 12, 2016

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A release operation synchronizes with an acquire operation on the same atomic variable and establishes,…

acquireReleaseConsume

memory_order_consume

July 9, 2016

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std::memory_order_consume is the most legendary of the six memory models. That's for two reasons. On…

criticalRegion

Acquire-Release Semantic

July 4, 2016

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With the acquire-release semantics, the memory model gets very thrilling. Because now, we do not have…

producerConsumer

Sequential Consistency applied

July 2, 2016

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I have introduced In the post Sequential Consistency the default memory model. This model, in which all…

atomicOperationsReadWriteEng

Synchronization and Ordering Constraints

June 28, 2016

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In this post, our tour through the c++ memory model goes one step deeper. Until now, the posts were only…

Atomics

June 22, 2016

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In addition to booleans, there is atomics for pointers, integrals, and user-defined types. The rules…

Latest news

C++26 Core Language: Small ImprovementsNovember 4, 2024 - 8:34 am
There are more small improvements in the C++26 language, which you should know. static_assert extension First, here’s the syntax of static_assert in C++11: static_assert(compile time predicate, unevaluated string) With C++26, the string can be a user-defined type having the following properties: static_assert can now be used with a format string. Here’s a nice example from […]
Placeholders and Extended Character SetOctober 28, 2024 - 10:19 am
Placeholders are a nice way to highlight variables that are no longer needed. Additionally, the character set of C++26 will be extended. Placeholders Structured bindings are a C++17 feature that allows you to bind multiple variables to the elements of a structured object. The following program demonstrates using tuples and structured bindings to return and […]
Contracts in C++26October 21, 2024 - 9:54 am
Contracts allow you to specify preconditions, postconditions, and invariants for functions. Contracts should already be part of C++20 but were removed in the standard meeting in Cologne. Here is what Herb Sutter said about contracts on Sutter’s Mill: “contracts is the most impactful feature of C++20 so far, and arguably the most impactful feature we […]
Reflection in C++26: Determine the LayoutOctober 14, 2024 - 9:42 am
Thanks to reflection, you can determine the layout of types. My examples are based on the reflection proposal P2996R5. Class Layout The following program determines the class layout of a few members. // classLayout.cpp #include <experimental/meta> #include <iostream> #include <utility> #include <vector> #include <array> struct member_descriptor { std::size_t offset; std::size_t size; bool operator==(member_descriptor const&) const […]
Reflection in C++26: Metafunctions for Enums and ClassesOctober 7, 2024 - 1:53 pm
Today, I continue my journey through reflection in C++26 and play with enums and classes. The names of the metafunctions to access an Enum or a Class member are often identical. Access the Members of an Enum The following program is based on one by Daveed Vandevoorde. Daveed is one of the fathers of reflection, […]
Reflection in C++26: MetafunctionsSeptember 30, 2024 - 10:14 am
Reflection offers many metafunctions that run at compile time. The metafunctions are declared as consteval. consteval creates a so-called immediate function. Each invocation of an immediate function creates a compile-time constant. To say it more directly. A consteval (immediate) function is executed at compile-time. Read more about consteval and constinit in my previous post: Two […]