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 […]
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 […]
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 […]
Today, I would like to introduce all the important aids that allow me and Beatrix to get through the day >> My ALS Journey so far << Aids Caregivers Of course, caregivers are not aids, but they still belong on this list. I can now have 24/7 care. This care is an incredible help for […]
My next mentoring program, “Embedded Programming with Modern C++,” starts on January 31st. Registration is open. Here are more details. Embedded Programming with Modern C++ The mentoring program consists of 16 stations. You have to invest at least 3 hours per week for each one. This means the program takes four months, and you can […]
Today, I continue my mini story about lock-free data structures. General Considerations From the outside, the caller’s responsibility (application) is to protect the data. From inside, the data structure is responsible for protecting itself. A data structure that protects itself so a data race cannot appear is called thread-safe. First, what general considerations must you […]
Before I dive into lock-free programming, there’s a little bit of theory necessary. A common problem in concurrency is the so-called ABA problem. That means you read a variable twice, which returns the same value each time, A. Therefore, you conclude that nothing changed in between. But you forgot the B. Let me first use […]
Displaying the address of an arbitrary pointer in C++ 20 fails but succeeds with C++26. C++20 Only void, const void, and std::nullptr_t pointer types are valid. If you want to display the address of an arbitrary pointer, you must cast it to (const) void*. // formatPointer20.cpp #include <format> #include <iostream> #include <string> int main() { […]
C++26 offers many small improvements around strings and string_views. First of all: What is a string_view? std::string_view A std::string_view is a non-owning reference to a string. It represents a view of a sequence of characters. This sequence of characters can be a C++ string or a C-string. In a typical way, C++17 offers four type […]
Today, I present a sad story, and I can only take it by humor. >> My ALS Journey so far << My Electrical Wheelchair I need an electric wheelchair badly. This wheelchair should also support standing and sleeping. With this wheelchair, I can move inside and outside my flat and visit friends, things I could […]