This talk is the 2026 edition of our series that highlights low-latency, networking, parallelism, and concurrency proposals to the C++ Standards Committee, especially those discussed in the Kona 2025, Croydon 2026, and Brno 2026 meetings. This talk from the Concurrency TS2 Editors, DG and SG14/19 chair will describe the following features and show how they can be used. It will also give their motivation, background, and their place within the overall framework of C++ low latency, networking, parallelism and concurrency:
Atomic Compare and Hazard Pointers Reclamation Control
- We discuss a proposal for atomic compare operations that clarify programmer intent and simplify static analysis by avoiding the unnecessary leakage of atomic values. We also explore how these operations complement recent proposals to enhance the expressiveness of atomics, such as the use of tagged pointers.
- We examine techniques for controlling C++26 hazard pointer reclamation, demonstrating how to offload retirement overhead to asynchronous executors to ensure predictable thread latency. We show how this capability can prevent specific deadlock scenarios and assess whether such controllers should be standardized or remain user-space patterns.
Twenty-One Years Without Sockets, The History of Networking in C++ and What We Learned Along the Way
- Go has standard networking. Rust has standard networking. C++ has been trying since 2005. This talk tells the twenty-one-year story in seventeen minutes: the library that shipped but never standardized, the dependency that blocked it, the coroutine revolution that changed the assumptions, the technical discovery that explains why I/O doesn’t fit the three-channel model cleanly, and the bridge that lets both models win. Three decision points, three lessons, one live question: how should coroutines and senders coexist for C++29? No villains. Just the story and the engineering. Networking is now finally a C++29 priority, so said the Direction Group’s P5000.
Out-of-Thin-Air (OOTA) Values.
- The memory models for high-level languages, including C++, C, Rust, and even Java, have been prone to out-of-thin-air values. For example, given two atomic integers X and Y, both initially zero, if one thread does a relaxed assignment from X to Y and the other does a relaxed assignment from Y to X, the mathematical C++ memory model does not rule out the outcome where both X and Y have the value 42. However, both communication and computation take time, and so we have proven that OOTA values cannot happen on real-world production-quality computer systems. This result makes compiler-writers’ lives easier, and also eases the jobs of those brave individuals pursuing the full mathematical OOTA problem by relieving them of the need to live within CPU and memory constraints of production-quality compilers.
Discussion
There are other features under discussion, but the features we will present seem close to approval, are particularly interesting, and/or are relatively non-controversial. We will show use cases for each and prognosticate their journeys to C++26 and beyond. This will help programmers in concurrency, lock-free programming, and low-latency applications understand how best to take advantage of each of these important facilities.
