Lifetime Safety Profile • Herb plans to revise the Lifetime Safety Profile as part of Cpp2Future of C++?Future of C++? C++ Core Guidelines’ Lifetime Safety ProfileFuture of C++? C++ Core Guidelines’ Simplified borrowing Hylo (formerly Val): Mutable Value SemanticsSwift’s Law of Exclusivity Future of C++? C++ Core Guidelines’ Lifetime Safety Profile Crubit: Adopting Rust’s Type System Simplified borrowing Hylo (formerly Val): Mutable Value SemanticsSwift’s Law of Exclusivity Future of C++? C++ Core Guidelines’ Lifetime Safety Profile Crubit: Adopting Rust’s Type System

FILE I/O: PAST, PRESENT AND FUTURE CPPCON OCTOBER 3RD 2023 GUY DAVIDSON @HATCAT01INTRODUCTIONS • Head of Engineering Practice at Creative Assembly • 1980 – Acorn Atom • ISO/IEC JTC1/SC22/WG21 • BSI buffered file IO? • How do we optimise unbuffered file IO? • How might the standard help us in future?AGENDA • Sub-megabyte days • More RAM, more disk capacity • Moving data into and out of RAM • buffered file IO? • How do we optimise unbuffered file IO? • How might the standard help us in future?SUMMARY • https://wg21.link/p1040 • https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3017.htm

thread yfutures/promises: “buffered channel” Promise promise; Future future = promise.Future(); reader.Read(); // Blocks! Channel::Writer writer = channel.Writer(); thread yfutures/promises: “buffered channel” Promise promise; Future future = promise.Future(); reader.Read(); // Blocks! Channel::Writer writer = channel.Writer(); thread yfutures/promises: “buffered channel” Promise promise; Future future = promise.Future(); future.Get(); // Blocks! Channel::Writer writer = channel.Writer();

it is finished, and generally causes some work to happen in the background before triggering some future action in the application (as opposed to normal synchronous functions, which do every- thing they There are many styles of asynchronous interfaces: • Callback argument • Return a placeholder (Future, Promise, Deferred) • Deliver to a queue • Callback registry (e.g. POSIX signals) Regardless of tornado.concurrent import Future def async_fetch_manual(url): http_client = AsyncHTTPClient() my_future = Future() fetch_future = http_client.fetch(url) def on_fetch(f): my_future.set_result(f.result().body)

tornado.autoreload — Automatically detect code changes in development tornado.concurrent — Work with Future objects tornado.log — Logging support tornado.options — Command-line parsing tornado.testing — Unit it is finished, and generally causes some work to happen in the background before triggering some future action in the application (as opposed to normal synchronous functions, which do everything they are returning). There are many styles of asynchronous interfaces: Callback argument Return a placeholder (Future, Promise, Deferred) Deliver to a queue Callback registry (e.g. POSIX signals) Regardless of which

IT WORKS* HOW IT WORKS* EXAMPLES: C++20 AND BEYOND EXAMPLES: C++20 AND BEYOND SUMMARY / FUTURE? SUMMARY / FUTURE? * BASED ON * BASED ON P1609R1 P1609R1 2MOTIVATION MOTIVATION 3 . 1WHAT IS JITTING? using meta = std::string; // [Future] Abstract Syntax Tree (AST) node 5 . 10READ–EVAL–PRINT LOOP (REPL) READ–EVAL–PRINT LOOP (REPL) using meta = std::string; // [Future] Abstract Syntax Tree (AST) node C++ 5 . 10READ–EVAL–PRINT LOOP (REPL) READ–EVAL–PRINT LOOP (REPL) using meta = std::string; // [Future] Abstract Syntax Tree (AST) node P1717: COMPILE TIME METAPROGRAMMING IN C++ P1717: COMPILE TIME

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414 17.6. future、任务和线程 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . await 关键字。 future 是一个现在可能还没有准备好但将在未来某个时刻准备好的值。（相同的概念也出现在 很多语言中，有时被称为 “task” 或者 “promise”。）Rust 提供了 Future trait 作为基础组件， 这样不同的异步操作就可以在不同的数据结构上实现。在 Rust 中，我们称实现了 Future trait 的类型为 future。每个 future 会维护自身的进度状态信息以及对 并恢复。在一个 async 块或 async 函数中，可以使用 await 关键字来 await 一个 future（即等待其就绪）。async 块或 async 函 数中每一个等待 future 的地方都可能是一个 async 块或 async 函数中断并随后恢复的点。检 查一个 future 并查看其值是否已经准备就绪的过程被称为 轮询（polling）。 其它一些语言，例如 C# 和 JavaScript，也使用

• Iterator • panic!, assert_eq ! ... • NonNull and all the usual pointer-related functions • Future � async/await • fence, AtomicBool, AtomicPtr, AtomicU32 ... • Duration • Box, Cow, Arc, Rc • the match register and raw interrupt status to busy-wait until a given time, e.g. 3 seconds in the future. (Call core::hint::spin_loop inside the loop .( 3 . � � � � � � � � � � � � � � � � � � � � : � � � � � � � � � � � � � � � � � � � � � . future � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � » polled « � � � � � � . Future � � � � � � � � � � � � � � � � � � � � � � �

solvers, and related algorithms. • Modern C++: • : Pseudo-random number generation • <future>: Task-Based Concurrency • : Parallel versions of certain STL algorithms 2Cancer and early 2)Task-based concurrency 13 • Each tumor is a parallel task: std::vectorfuture> • For each future object, call get() to obtain a 2d array. two different tumorsEigen::ArrayXXd initial_population, const Eigen::ArrayXXd& transition_rates); int main(){ //... std::vectorfuture> sample_tumor_par; for (auto k : seeds) sample_tumor_par.emplace_back(std::as

data // Send an asynchronous request. $req = $client->createRequest('GET', 'http://httpbin.org', ['future' => true]); $client->send($req)->then(function ($response) { echo 'I completed! ' . $response; }); By providing the future request option to a request, you can send requests asynchronously using the promise interface of a future response. $client->get('http://httpbin.org', ['future' => true]) ->then(function the second argument. Synchronous Requests Guzzle sends synchronous (blocking) requests when the future request option is not speci- fied. This means that the request will complete immediately, and if