Library Quick Reference  Founder of the Belgian C++ Users Group (BeCPP) C++204 Agenda  C++23 Core Language  Explicit Object Parameters  if consteval  Multidimensional Subscript Operator  Attributes Before Line Splicing  C++23 Standard Library  String Formatting Improvements  Standard Library Modules  std::flat_(multi)map / std::flat_(multi)set  std::mdspan  std::generator  basic_string(_view)::contains() Containers Heterogeneous Erasure  Removed Features  Garbage Collection SupportC++23 Core Language6 Agenda  C++23 Core Language  Explicit Object Parameters  if consteval  Multidimensional Subscript

find_package(OpenCV REQUIRED COMPONENTS core videoio) • 查找名为 OpenCV 的包，找不到就报错，且必须具有 OpenCV::core 和 OpenCV::videoio 这 两个组件，如果没有这两个组件也会报错。 • find_package(OpenCV REQUIRED OPTIONAL_COMPONENTS core videoio) • 查找名为 OpenCV OpenCV 的包，找不到就报错，可具有 OpenCV::core 和 OpenCV::videoio 这两个 组件，没有这两组件不会报错，通过 ${OpenCV_core_FOUND} 查询是否找到 core 组件。 find_package 说是找“包”，到底是在找什么？ • find_package(OpenCV) 实际上是在找一个名为 OpenCVConfig.cmake 的文件。 • 注：出于历史兼容性考虑，除了 Qt5Config.cmake 是你安装 Qt5 时，随 libQt5Core.so 等实际的库文件，一起装到你的 系统中去的。以我的 Arch Linux 系统为例： • 包配置文件位于 /usr/lib/cmake/Qt5/Qt5Config.cmake 。 • 实际的动态库文件位于 /usr/lib/libQt5Core.so 。 find_package 说是找“包 (package)”

What can we cover today? oRise of "JavaScript-driven Native" oIntro to NativeScript oNativeScript core concepts o“Hello World” oExtending with plugins oDebugging JavaScript Why are we here? How did NativeScript Everything Runs on UI Thread* • Plugins created with native code • React Support • API Access via Native Modules • UI Thread vs JS Thread • Angular/Vue/Vanilla vs React • Progress vs Facebook • Apache 2.0 vs Intro to NativeScript What is it? How does it work? 2013 2014 2015 2016 2017 Early prototype s “Core” engineerin g Public launch Adoption ramp-up Mass adoption Project Timeline NativeScript

it also provides the knobs needed to fine tune to different cases. Flexible Tokio Core Queue-Based Modules in Tokio • Channel • Scheduler • Tokio uses Channel for communication between threads Senders Senders Receive Receivers Perf Gaps: CAS(Compare And Swap) can't perfectly scale with core count. Tokio Channel • Each worker has own run queue • Steal when own run queue is empty From Adding new entries from any core or thread • Picking the next entry by any core or thread Conclusion: • DLB channel scales with core count much better than SW channels • Core count >2 shows advantage

standard passed ISO voting, expected to be formally published by the end of 2020.4 Agenda  Modules  Ranges  Coroutines  Concepts  Lambda Expression Changes  [=, this] as Lambda Capture   co_yield  char8_t  New identifiers:  import  moduleModules7 Modules  Advantages  Replace header files  Modules explicitly state what should be exported (e.g. classes, functions, …) names, same name in multiple modules will not clash  Modules are processed only once  faster build times  Preprocessor macros have no effect on, and never leak from, modules  Order of module imports

is now feature complete • All features under /std:c++20 switch are production ready including modules, coroutines, concepts • C++20 features awaiting DR resolution are available for now under /std:c++latest Concepts and Ranges Sy Brand, Christopher Di Bella – `Online _3 Mon, Oct 25 – 3:15pm Implementing C++ Modules: Lessons Learned, Lessons Abandoned Cameron DaCamara, Gabriel Dos Reis – _2 Thu, Oct 28 – 3:15pm and basic_string_view • Other small features 🕙 Coming next for C++23 • STL • Standard library modules • Coroutines 💡 C++98* * with /permissive- 💡 C++11 💡 C++14 💡 C++17 💡 C++20* *awaiting DR resolution

能不如 Tokio smol Rayon 并非异步运行时。它通过同步 多线程模型提供了并行迭代器功能， 适用于处理 CPU 密集型计算任务 rayon 现有框架无法完美适配移动端（一） Core Thread Thread Worker Worker task task Local queue Local queue Tokio 采用了如右图这种 GMP 模式： • 一核可以绑定多线程，每个线程拥有一个 queue Core 高权重线程 Worker Worker 任务优先级调度 根据工作线程的优先级进行绑核（大小核） • 高优先级任务在大核执行，高性能 • 低优先级任务在小核执行，节省能耗 Task priority and quality of service Big Core Little Core 高优先级线程 低优先级线程 普通优先级线程 Set core-affinity

Crypto Core 利用 Rust 重塑移动应用开发 RCC_android RCC_ios https://github.com/KeystoneHQ/rust-crypto-core https://github.com/KeystoneHQ/rcc_android https://github.com/aaronisme/rcc_ios Rust Crypto Core Core

More components will be open source later • Support more Linux distributions • Build IPVS kernel modules in Ubuntu, Centos • IPVS-eBPF next generation on the way • Implement IPVS SNAT with eBPF without

announcements Take our survey https://aka.ms/cppconOur Sessions Monday 25th • Implementing C++ Modules: Lessons Learned, Lessons Abandoned – Cameron DaCamara & Gabriel Dos Reis Tuesday 26th • Documentation