C++26 Preview Jeff Garland 1Status of c++26 - it'll ship on time it is an immutable property of committee process 'train model' - what is ready ships there is a plan: much committee work has gone virtual plenary sessions / year opened the door to participation! http://wg21.link/P0592 2Status of c++26 - it'll ship on time it is an immutable property of committee process 'train model' - what is ready participation! http://wg21.link/P0592 c++26 schedule 2022-02 meeting (Kent Wa) was last c++ 2023 meeting 2025-02 –> c++26 feature freeze – just months away! 2025-06 –> c++26 dra� ships June to Feb 2026– national

foundations Outline of an implementation Conclusion High-Performance Numerical Integration in the Age of C++26 Vincent Reverdy Laboratoire d’Annecy de Physique des Particules, France September 20th, 2024 LUTH indexer [0, 0] = coefficient (/∗ value ∗/), // ... >; need to collapse to the same type! C++26 proposal that will help Language constructs to uniquely order types See P2830R4: Standardized Constexpr optimize during the compilation process: doable in C++23, but easier with reflection and meta_info in C++26 Conclusion We can have a nice unified interface corresponding to Butcher’s Tableau: aij, bn j ,

C++26 for C++14 Developers: STL-Preview Author Tony Lee Reply-To cosgenio@gmail.com 1. Introduction Since the introduction of modern C++ in 2011, the language has seen introduces stl-preview２, a library that backports most of the latest STL features (including those from C++26) to C++14 (but not limited to), ensuring compatibility with existing STL implementations and bridging stl-preview currently implements 281 out of 690 STL functions and classes introduced between C++17 and C++26 in C++14. This includes ranges, concepts, span, and expected. It has been tested on various compilers

and ); // ✔ 24 / 58Value-based TMP - tuple_element Value-based TMP - tuple_element C++26 - Pack indexing - C++26 - Pack indexing - template struct tuple_elementC++26* - Reflection for C++26* - Value-based Metaprogramming Value-based Metaprogramming Meta functions for Reflection generation) https://wg21.link/p2996 https://wg21.link/p2996 38 / 58Reflection for C++26* - Reflection for C++26* - https://wg21.link/p2996 https://wg21.link/p2996 ^^T // reflection operator (reflexpr)

(P3125; Maged) 4. Parallel Range algorithms (P3179; Michael), may be Parallel Algorithms (P2500)C++26: Atomic Min/MaxC++26: Improving C++20 Concurrency primitives atomic min/max (P0493)Atomic min/max all threads.Current Status, Next Steps, & Conclusion Proposal in flight since 2016, aiming for C++26 Current revision: P0493R5 (February 2024) Implementation experience in Clang Open questions: ● Additional functions for more specific needsHazard Pointer Extensions beyond C++26Hazard Pointers in C++26 -- Background Hazard pointers protect dynamic objects from being reclaimed, allowing safe access

assert("post " && (size() == old_size - 1));
 } 40© 2023 Adobe. All Rights Reserved. Maybe someday | C++26? 41 void pop_back() { assert("pre " && (size() > 0)); #ifndef NDEBUG auto old_size assert("post " && (size() == old_size - 1));
 }© 2023 Adobe. All Rights Reserved. Maybe someday | C++26? 42 void pop_back() { assert("pre " && (size() > 0)); #ifndef NDEBUG auto old_size assert("post " && (size() == old_size - 1));
 }© 2023 Adobe. All Rights Reserved. Maybe someday | C++26? void pop_back() { assert("pre " && (size() > 0)); #ifndef NDEBUG auto old_size

code generation (aka ‘injection’/…)  Contracts  means “some initial parts already voted into C++26”3 Major advances are on track  std::execution (concurrency and parallelism)  Type and memory decade  Contracts  “ i iti l t l d t d i t C++26”4 memory safety attacks “cold” cyberwar, in progress 1  2 includes • timing: starting in C++26 • technical: UB • this week: >dozen talks • 3: happen” Usual examples nasal daemons, format c: Actual bad examples time travel, leaking secrets C++26 introduces a new tool: erroneous behavior “Well-defined as being Just Wrong” Not undefined  no time

implementation status? • Did the TS process work for us? 16 © 2021. 17 Hazard Pointers in Concurrency TS2, C++26, and beyond 17 © 2021. 18 Hazard Pointers in a Nutshell Used to protect access to objects that may optimization). • No customization needed in Folly so far. 24 © 2021. 25 Hazard Pointers Proposal for C++26 Minimalist useful subset of TS2: • Supports asynchronous reclamation • Compatible with external link synchronous reclamation (for now) • Can be extended 25 © 2021. 26 Hazard Pointers Proposal for C++26 class hazard_pointer_domain { public: hazard_pointer_domain() noexcept; explicit hazard_pointer_domain(

Interface in C++26 • Basics • Using with Eigen Outline Daniel Hanson CppCon 2024 2• This presentation is on solving problems using • The Eigen linear algebra library • stdBLAS in C++26 • Not affiliated reside in contiguous memory ➢ std::vector ➢ Eigen::VectorXd ➢ std::mdarray (p1684) (C++26) • stdBLAS (P1673), C++26 • A free function linear algebra interface based on the BLAS • Matrix represented by a 2-D mdspan • Default BLAS with major compilers/library vendors A Little History: C++23 and C++26 Daniel Hanson CppCon 2024 8The Eigen Library Daniel Hanson CppCon 2024 9• A C++ template library

characters as ascii numbers report_error();User Generated Error Messages C++26 enables user generated error messages in static_assert: message.size() is implicitly convertible to } else { static_assert(sizeof(value) == 0); } }, user_action); }Reflection for C++26 (P2996R1) Proposal to add static reflection to C++. • Reflection operator ^T that returns the meta members_of(info type_class) -> vector; enumerators_of(info type_enum) -> vector; /*...*/C++26 Reflection – Proxy Types Generate a proxy type with define_class template consteval auto