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
	P3125R5	constexpr pointer tagging	H. Dusíková	LEWG LWG
Mailing Date 2026-05 Pre-Brno Author(s) Hana Dusíková Target Audience LEWG LWG Revisions R6 Tracking issue View on GitHub Abstract Pointer tagging is widely known and used technique ([Glasgow Haskell Compiler](https://takenobu-hs.github.io/downloads/haskell_ghc_illustrated.pdf), LLVM's `[PointerIntPair](https://github.com/llvm/llvm-project/blob/8e5aa538caccef167e8096b2173fdaf2be9cc129/llvm/include/llvm/ADT/PointerIntPair.h#L80)`, `[PointerUnion](https://github.com/llvm/llvm-project/blob/8e5aa538caccef167e8096b2173fdaf2be9cc12
	P3377R0	constexpr `reinterpret_cast` partial replacements	H. Dusíková, G. Ažman	EWG LEWG
Mailing Date 2026-05 Pre-Brno Author(s) Hana Dusíková, Gašper Ažman Target Audience EWG LEWG Tracking issue View on GitHub Abstract \| functionality \| runtime only (current status) \| runtime & constexpr compatible replacement \| status \| \| --- \| --- \| --- \| --- \| \| pointer ↔︎ integer \| `intptr_t * iptr = reinterpret_cast<intptr_t>(ptr); auto * optr = reinterpret_cast<pointer>(iptr);` \| — \| not proposed \| \| pointer tagging \| `auto tptr = reinterpret_cast<pointer>( reinterpret_cast<intptr_t>(ptr) \\| 0b1u); auto tag = static_cast<b
	P3818R2	constexpr exception library which is unsurprising in potentially constant initialization	H. Dusíková	EWG LEWG
Mailing Date 2026-05 Pre-Brno Author(s) Hana Dusíková Target Audience EWG LEWG Tracking issue View on GitHub Abstract To make `constexpr` exception support complete, and allow all functionality withing constant evaluation. This paper was seen in previous revision by LEWG. It didn't get consensus and most of the group prefered the conservative approach of removing `constexpr` from `std::uncaught_exception()` and `std::current_exception()`. The group asked me to revisit this again for C++29.
	P3852R1	constexpr `is_pointer_within` memory area	H. Dusíková	LEWG
Mailing Date 2026-05 Pre-Brno Author(s) Hana Dusíková Target Audience LEWG Tracking issue View on GitHub Abstract At first maybe this does seem as somehow arcane or esoteric. But this is a problem worth solving and it will make C++ a bit more expressive.
	P3933R1	constexpr `std::hive`	H. Dusíková, NylteJ	LEWG
Mailing Date 2026-05 Pre-Brno Author(s) Hana Dusíková, NylteJ Target Audience LEWG Tracking issue View on GitHub Abstract C++ users are often surprised by missing functionality available during constant evaluation, sometimes there is no real reason in the language, it's just no one wrote a paper making the thing `constexpr`. Anecdotally this is often surprise to Jason Turner's students when they start experimenting with `constexpr` code.
	P4013R0	constexpr `any` of all the things	H. Dusíková	LEWG
Mailing Date 2026-05 Pre-Brno Author(s) Hana Dusíková Target Audience LEWG Tracking issue View on GitHub Abstract Often you just need to pass a value around, but not interact with it, for that in C++ you have multiple options: template (and keep the type information intact), inheritance (and being force to use intrusive inheritance in your types), passing allocated `(const) void *` pointer (and managing its lifetime), alternatively use `std::unique_ptr` or `std::shared_ptr` with custom deleters, or use a poly

Showing 6 of 6 papers · source: open-std.org

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