The Wonderful World of Designing a USB Stack Using Modern C++

by Madeline Schneider

Have you ever wondered how to design a library to abstract and manage complex communication protocols like USB? Have you ever wondered which parts of a protocol need to be hardware abstractions and which parts are hardware agnostic? Well you’re in luck, my mentor and I have designed a USB stack from the ground up in modern C++! We found that the public offerings did not meet our needs. Our requirements are:

• Resource efficient
• Portable
• Modular
• Convenient to use
• Distributable via single pre-built binary using conan
• Without allocations after initialization

In this talk you’ll learn the basics of how USB works at the lowest level from a software perspective. You’ll learn why malleability and freedom are so important for USB device development and how C++ makes such a library design easy to implement. Embark with me on a deep-dive into shaping a library where complexity runs wild. This talk will have lessons on library and API design in situations where the degrees of freedom are vast and all parts must magically fit together. By the end, you’ll carry away practical patterns for taming vast design spaces—skills that apply to any ambitious library, far beyond USB.

Can Standard C++ Replace CUDA for GPU Acceleration?

by Elmar Westphal

On top of the woes of multi-threaded programming itself, coding for GPUs used to be about dealing with kernels, separate memory domains, warps, blocks and other strange things. Later, life became easier and you could sprinkle in a bunch of pragmas, hoping that your favorite language extension would deal with all of this for you, and better memory model abstractions came up that were less painful to deal with. In recent years, new drivers (seemingly) levelled the boundaries between memory domains and new compilers allow us to deploy code to the GPU using standard C++ execution policies. The performance of the generated code is often similar to that of its CUDA-C++ counterpart. Of course there is no magic bullet to shoot at your (legacy) code and there are caveats, but come and see how using standard parallelism (also) for programming GPUs makes it a lot easier to write portable and more future-proof high-performance C++ code.

C++: Some Assembly Required

by Matt Godbolt

Join Matt in exploring how the C++ ecosystem has evolved through the interplay of intentional design and emergent collaboration. Standards committees craft language features and compiler teams implement them, but something amazing happens in the spaces between: tools appear, communities form, and solutions emerge that nobody quite planned for. What started as individual developers solving their own problems has grown into an interconnected ecosystem that shapes how we all write C++.

From documentation to testing, from build systems to package managers, we'll examine how the C++ community has assembled itself around shared pain points and accidental standards. Using examples and perhaps too many rainforest metaphors, this talk celebrates not just the language we've built, but the organic ecosystem that's grown up around it. Come discover why C++'s greatest strength might be that it's always required some assembly.

How C++ Finally Beats Rust at JSON Serialization

by Daniel Lemire & Francisco Geiman Thiesen

JSON, or JavaScript Object Notation, has become a cornerstone for storing and exchanging data. Its appeal lies in its simplicity—human-readable text that elegantly captures structured data through attribute-value pairs and arrays: {"age": 5, "name": "Daniel", "toys": ["wooden dog", "little car"]}. JSON is intuitive yet powerful. But ingesting and producing JSON can turn into a performance choke point. In C++, it can be a tedious, error-prone task. Programmers wrestle with unexpected content, manually mapping data to and from native structures, all while striving for speed and safety.

With languages like Java, C#, Zig, Rust, or Python, JSON serialization and deserialization typically requires far less work. In particular, Rust's serde library blends convenience with high speed. We wish for a C++ library to automatically handle JSON production and consumption, seamlessly tied to native data structures. It is not merely to simplify life for developers; it is also about crafting code that is both fast and solid, generated at compile time by a battle-tested library.

Thankfully, C++ might soon be getting reflective metaprogramming (  PR2996  ). Leveraging the  experimental Bloomberg LLVM fork  with reflective metaprogramming, we have built a full-fledged implementation—complete with tests, benchmarks, and documentation. Our goal is to have production-ready code the moment mainstream compilers catch up. The results speak for themselves: we are parsing JSON directly into C++ structures at gigabytes per second, outpacing even mature heavyweights like Rust's serde. Better yet, the conversion between C++ data structures and JSON is fully automated, thanks to metaprogramming. It has the potential to be a leap forward for C++ in the data-driven age. Unfortunately, there are still problems and limitations: we present them and provide some solutions.

Why Every C++ Game Developer Should Learn SDL 3 Now

by Mike Shah

The C++ programming language does not have a standard graphics library, However, there exists many popular graphics frameworks for cross-platform graphics. In this talk, I will provide an introduction to the Simple Directmedia Layer (SDL) library, which has at the start of 2025 released version 3. This library for several decades has been a standard in the games and graphics industry. Throughout this talk, I will show how to get started with the library, some more advanced examples (including compiling graphics applications to web), and then talk about what a standard graphics library could look like in C++, or if it is even necessary. I will also talk about the 3D GPU library in SDL3. Attendees will leave this talk ready to build multimedia / game applications and with an understanding on if SDL3 is the right tool for them.

Implementing Your Own C++ Atomics

by Ben Saks

Atomic objects are extremely useful for concurrent programming. Unfortunately, some embedded toolchains like AVR-GCC omit portions of the C++ Standard Library, including headers like ＜atomic＞ .This makes it much harder to program concurrent software on these platforms, since many tutorials and open-source libraries assume Standard Library support. For example, these talks from past CppCons present lock-free data structures and algorithms that rely strongly on lock-free instantiations of std::atomic＜T＞:

Single Producer Single Consumer Lock-free FIFO From the Ground Up – Charles Frasch – CppCon 2023
Introduction to Wait-free Algorithms in C++ Programming – Daniel Anderson – CppCon 2024
User API & C++ Implementation of a Multi Producer, Multi Consumer, Lock Free, Atomic Queue – Erez Strauss – CppCon 2024

This session will show you how to implement your own atomic types in the absence of library support. These atomic types can greatly expand the number of tutorials and open-source libraries available for you to use. A clear understanding of how atomic types are implemented will also help you use objects of those types more effectively on platforms that do provide native support.

Back to Basics: Custom Allocators Explained - From Basics to Advanced

by Kevin Carpenter

Effective memory management is crucial for building efficient and reliable C++ applications. Custom memory allocators provide a powerful tool for optimizing memory usage, reducing fragmentation, and improving performance. This talk will explore the intricacies of memory allocation in C++, from the basics of dynamic memory management to the implementation of custom allocators. Attendees will gain insights into the standard allocator model, techniques for designing custom allocators, and practical examples of their use in real-world applications.

Join us to unlock the full potential of memory management in your C++ projects.

Cache Me Maybe: The Performance Secret Every C++ Developer Needs

by Michelle D'Souza

Calling all code detectives! Grab your trench coats and magnifying glasses ... it's time to crack the case of sluggish C++ performance. In this thrilling investigation, we'll uncover the hidden world of your computer's built-in cache and how to harness it to turbocharge your code.

We'll comb through the fundamentals of caches like seasoned sleuths, uncover clues on optimizing access patterns, and interrogate suspects like false sharing and cache unfriendly data structures. We will also examine benchmark evidence based on real-world production code, exposing how each technique delivers the goods.

By the end of this mission, you'll be armed with a detective's toolkit of cache savvy strategies, ready to solve cross-platform performance mysteries and bring blazing fast code to justice. Cache you at this session, maybe!

Matrix Multiplication Deep Dive || Cache Blocking, SIMD & Parallelization

by Aliaksei Sala

Matrix multiplication is a fundamental operation in scientific computing, game development, AI, and numerous high-performance applications. While its mathematical definition is simple, achieving optimal performance in C++ is far from trivial.

In this talk, we will explore different optimization techniques for matrix multiplication, from naive implementations to highly tuned versions leveraging modern hardware features. We will cover key performance-enhancing strategies such as loop unrolling, cache blocking, SIMD vectorization, parallelization using threads and more. Through benchmarking and profiling, we will measure the real impact of these optimizations.

By the end of this session, attendees will gain insights into two critical questions:

How hard is it to implement an optimized matrix multiplication in C++? How effective is C++ for achieving peak performance in this task?

This talk is suitable for developers interested in performance optimization, computational efficiency, and modern C++ techniques for numerical computing.

Practical Reflection With C++26

by Barry Revzin

With the adoption of Reflection for C++26, the landscape of what is possible has shifted. This talk will focus on implementing Struct-of-Arrays for an arbitrary aggregate, but will also take some detours to cover some techniques that will prove useful for solving a wide range of problems.