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
	P3104R5	Bit permutations	J. Schultke	LWG
Mailing Date 2026-05 Pre-Brno Author(s) Jan Schultke Target Audience LWG Revisions R6 Tracking issue View on GitHub Abstract The C++ bit manipulation library in `<bit>` is an invaluable abstraction from hardware operations. Functions like `countl_zero` help the programmer avoid use of intrinsic functions or inline assembly.
	P3568R2	break label; and continue label;	J. Schultke	EWG SG22
Mailing Date 2026-05 Pre-Brno Author(s) Jan Schultke Target Audience EWG SG22 Tracking issue View on GitHub Abstract While C++ already has a broad selection of control flow constructs, one construct commonly found in other languages is notably absent: the ability to apply `break` or `continue` to a loop or `switch` when this isn’t the innermost enclosing statement. This feature is popular, simple, and quite useful:
	P3642R5	Carry-less product: std::clmul	J. Schultke	LEWG
Mailing Date 2026-05 Pre-Brno Author(s) Jan Schultke Target Audience LEWG Revisions R6 R4 Tracking issue View on GitHub Abstract [Carry-less multiplication](https://en.wikipedia.org/wiki/Carry-less_product) is a simple numerical operation on unsigned integers. It can be a seen as a regular multiplication where `xor` is being used as a reduction instead of `+`.
	P3666R4	Bit-precise integers	J. Schultke	LEWG CWG
Mailing Date 2026-05 Pre-Brno Author(s) Jan Schultke Target Audience LEWG CWG Revisions R3 Tracking issue View on GitHub Abstract In distant history, there have been various attempts at standardizing multi-precision integers in C++, such as [[N1692]](https://wg21%2elink/n1692) "A Proposal to add the Infinite Precision Integer to the C++ Standard Library", [[N1744]](https://wg21%2elink/n1744) "Big Integer Library Proposal for C++0x", and [[N4038]](https://wg21%2elink/n4038) "Proposal for Unbounded-Precision Integer Types", al
	P3724R4	Integer division	J. Schultke	LEWG
Mailing Date 2026-05 Pre-Brno Author(s) Jan Schultke Target Audience LEWG Revisions R3 Tracking issue View on GitHub Abstract C++ currently only offers truncating integer division in the form of the `/` operator. However, other rounding modes have various use cases too, and implementing these as the user can be surprisingly hard, especially when integer overflow needs to be avoided, and negative inputs are accepted.
	P3737R4	std::array is a wrapper for an array!	J. Schultke	LEWG
Mailing Date 2026-05 Pre-Brno Author(s) Jan Schultke Target Audience LEWG Revisions R3 Tracking issue View on GitHub Abstract The `std::array` class template has established itself as a de-facto replacement for "builtin arrays" or "C-style arrays" in many code bases. This also means that it is frequently taught to novice programmers, with an explanation along the lines of:
	P3876R2	Extending <charconv> support to more character types	J. Schultke, P. Bindels	SG16
Mailing Date 2026-05 Pre-Brno Author(s) Jan Schultke, Peter Bindels Target Audience SG16 Revisions R1 Tracking issue View on GitHub Abstract Support for `char8_t` and other Unicode character types in `std::to_chars` and `std::from_chars` is clearly useful. File formats such as JSON require the use of Unicode character encodings, so an application that deals with JSON may want to use `char8_t` in its APIs and internally. However, when attempting to use `char8_t` for this purpose, one quickly runs into problems:
	P3891R1	Improve readability of the C++ grammar by adding a syntax for groups and repetitions	J. Schultke	CWG LWG
Mailing Date 2026-05 Pre-Brno Author(s) Jan Schultke Target Audience CWG LWG Tracking issue View on GitHub Abstract The current C++ syntax notation as specified in [[syntax]](https://eel.is/c++draft/syntax) and summarized in [[gram]](https://eel.is/c++draft/gram) has only a handful of features:
	P3935R1	Rebasing <cmath> on C23	J. Schultke	SG22
Mailing Date 2026-05 Pre-Brno Author(s) Jan Schultke Target Audience SG22 Revisions R2 Tracking issue View on GitHub Abstract [[P3348R4]](https://wg21%2elink/p3348r4) rebased the C++26 standard on C23; it previously referred to C17. However, this process was deliberately left incomplete: some of the new C23 `<math.h>` features are only used by decimal floating-point types, or they require core language changes, etc.
	P3969R1	Fixing std::bit_cast of types with padding bits	J. Schultke	EWG LEWG
Mailing Date 2026-05 Pre-Brno Author(s) Jan Schultke Target Audience EWG LEWG Revisions R2 R0 Tracking issue View on GitHub Abstract > The following use of `std::bit_cast` has undefined behavior at compile time: > > ```cpp > constexpr auto x = std::bit_cast<__int128>(0.0L); // GCC accepts (x = 0), Clang rejects > ``` > > That is because an 80-bit x87 `long double` has 6 bytes of padding, and it is undefined behavior to map those padding bits onto non-padding bits in the destination type via `std::bit_cast`. [[bit.cast]](https:/
	P4231R0	Unified floating point rounding proposal	H. Boehm, G. Davidson, J. Schultke	LEWG SG6
Mailing Date 2026-05 Pre-Brno Author(s) Hans Boehm, Guy Davidson, Jan Schultke Target Audience LEWG SG6 Tracking issue View on GitHub Abstract We propose the addition of the following struct. Actual wording is still left as future work (some of which can be taken from p3864). This is basically identical to P2746, except that we constrain operations to be IEEE conformant whenever is_iec_559 is `true`.

Showing 11 of 11 papers · source: open-std.org

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