WG21 PAPERS

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Filter and export papers from the C++ Committee’s monthly mailings by time frame and audience using the options below, or refine your export further with the Select button. Links point directly to the official WG21 papers on open-std.org.

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Select	Paper	Title	Authors	Audience
	P3983R2	simd object representation	D. Towner, R. Arutyunyan	LEWG LWG SG1
Mailing Date 2026-05 Pre-Brno Author(s) Daniel Towner, Ruslan Arutyunyan Target Audience LEWG LWG SG1 Revisions R1 R0 Tracking issue View on GitHub Abstract The Working Draft makes `simd` types trivially copyable types, which allows `std::bit_cast` operations. However, the object representation is unspecified, making the results similarly unspecified.
	P4214R0	Composable Correctness and Progress Guarantees	L. Teodorescu	SG1
Mailing Date 2026-05 Pre-Brno Author(s) Lucian Radu Teodorescu Target Audience SG1 Tracking issue View on GitHub Abstract Correctness is usually harder to discuss than the individual properties from which it is built. Following Lamport’s division of correctness into safety and liveness [[Lamport77]](https://lamport.azurewebsites.net/pubs/proving.pdf), this paper argues that C++ standardization should treat progress guarantees as part of the correctness contract of concurrency facilities.
	P4215R0	Primitives for Non-Local Concurrency	L. Teodorescu	SG1
Mailing Date 2026-05 Pre-Brno Author(s) Lucian Radu Teodorescu Target Audience SG1 Tracking issue View on GitHub Abstract C++26 senders provide a vocabulary for composing asynchronous work, but they do not by themselves provide sender-native equivalents of synchronization primitives that impose non-local concurrency constraints. Programs still need to serialize unrelated operations, bound concurrency across independently submitted work, wait for readiness, and coordinate completion or phase boundaries.
	P4217R0	when_all() is just just()	R. Leahy	LEWG SG1
Mailing Date 2026-05 Pre-Brno Author(s) Robert Leahy Target Audience LEWG SG1 Revisions R1 Tracking issue View on GitHub Abstract The standard currently specifies, by fiat, that `std::execution::when_all()` is ill-formed (§33.9.12.12 [exec.when.all]):
	P4221R0	Atomic Compare	M. Michael, P. McKenney, M. Wong	SG1
Mailing Date 2026-05 Pre-Brno Author(s) Maged Michael, Paul McKenney, Michael Wong Target Audience SG1 Revisions R3 R2 R1 Tracking issue View on GitHub Abstract This paper proposes adding `compare` and `compare_load` member functions to `std::atomic<T>`. These functions perform an atomic comparison of the atomic object's value with an expected value, following the same bitwise comparison semantics as `compare_exchange_strong`, but without writing a new value to the atomic object. The `compare_load` variant also updates the expected argument on failure. Th
	P4223R0	Towards senders in interfaces	I. Petersen	SG1
Mailing Date 2026-05 Pre-Brno Author(s) Ian Petersen Target Audience SG1 Tracking issue View on GitHub Abstract * Separation of interface and implementation; the primary need identified in this paper is the ability to separate what an async function does (its interface) from how it does it (its implementation). The problem with the existing senders is that their types reflect the fully composed computation they represent so it is impossible to achieve this separation with the status quo.
	P4230R0	Implementability of P0943's C++ stdatomic.h	H. Boehm	LEWG SG1
Mailing Date 2026-05 Pre-Brno Author(s) Hans Boehm Target Audience LEWG SG1 Tracking issue View on GitHub Abstract There has been a lot of discussion arguing that the C++23 spec essentially forces ODR violations. by implementing atomics as both a struct/class (in C++) and a scalar (in C) IMO, that depends on your perspective. If you view C code as also C++ code, then ODR violations in a combined C with C++ program make sense. This is the common view of C types in C++.

Showing 7 of 7 papers · source: open-std.org

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