CppCon 2021 CppCon 2021 What’s New In ‘ Visual Studio 64-bit IDE, C++20, WSL2, and More Marian Luparu (he/him) @mluparu Sy Brand (they/them) @TartanLlama C++ Product Team, Microsoft @VisualC https://aka Code Safety 3. Cross-platform development 4. Developer and Team Productivity Static Analysis ✴ New and improved checkers in MSVC Code Analysis • Returning a local variable with std::move • Path-sensitive Safety 3. Cross-platform development 4. Developer and Team Productivity New in Visual Studio 2022 • 64bit IDE • New themes available https://aka.ms/vsthemes • Or bring your own VSCode theme

What’s new with NativeScript! ? 2.3 is ready to rock! ? TJ and Jen ? @tjvantoll @jenlooper What’s new in…. • Core ? • Tooling ? • Plugins ? • Community ? • Apps ? Core ? Core ? • CLI updates Code Samples ? UI for NativeScript ??? • We already have... UI for NativeScript ??? • Dataform is new! Telerik Platform ? Plugins ? Plugins ? • 250+ plugins on npm! OAuth? • https://github.com/a

Existing integer literal suffixes: U, L, UL, LL, and ULL  New:  uz or UZ: creates a std::size_t integer literal  z or Z: creates a signed integer type corresponding to std::size_t22 Literal Suffix for size_t Erasure  Removed Features  Garbage Collection Support26 #elifdef, #elifndef, and #warning  New preprocessor directives  Existing:  #ifdef id shorthand for #if defined(id)  #ifndef id shorthand Heterogeneous Erasure  Removed Features  Garbage Collection Support44  Defined in  New adaptors on top of basic sequence containers  Associative container interface (similar to std::map)

(https://youtu.be/c7DT28TV0AY)9 Part II: Calendrical Types10 Calendrical Types ([time.cal]) • Lots of new class types • chrono::day • chrono::month • chrono::year • chrono::month_day • chrono::weekday • Output: 2021-10-28 Nov/Thu[4] 2020/Feb/last 29 2021/Feb/last 2814 Some examples: operator/ with new chrono literals #include #include using namespace std::chrono; int main() { Apr 13 May 11 Jun 08 Jul 13 Aug 10 Sep 14 Oct 12 Nov 09 Dec 1416 Why calendrical types? Type Safety The “simple” calendrical types (e.g., day, month, year) are very straightforward – what’s

Quick Reference  Founder of the Belgian C++ Users Group (BeCPP)3 C++20 C++20 is big! Lots of new features! On Friday September 4, 2020, the C++20 standard passed ISO voting, expected to be formally std::atomic_ref  Designated Initializers  Spaceship Operator <=>  Range-based for Loop Initializer  Non-Type Template Parameters  [[likely]] and [[unlikely]]  Calendars & Timezones  std::span  Feature Small Standard Library Additions5 Agenda  New keywords:  concept  requires  constinit  consteval  co_await  co_return  co_yield  char8_t  New identifiers:  import  moduleModules7

r1 = ratio<1, 60>; // 1/60 using r2 = ratio<1, 30>; // 1/30 using result = ratio_add::type; cout << format("sum = {}/{}", result::num, result::den);// 1/20  Comparisons with ratio_equal cout << format("r2 < r1: {}", res::value); // false8 Compile-Time Rational Numbers  Predefined SI type aliases: using atto = ratio<1, 1'000'000'000'000'000'000>; using femto = ratio<1, 1'000'000'000'000'000>; = rational constant  template > class duration {...}  Rep = type to represent number of ticks11 Durations – Examples  Duration with ticks of 1 second: duration

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- Rust 的形式化语义模型 Outline Background • RustBelt Project • Rust Types Overview Rust Semantics • Type System • The own Predict • Exclusive Ownership & Mutable Borrow Examples • Rc Logics • Hoare &mut T &T mutable borrow immutable borrow coercion move mutable reborrow reborrow () drop new exclusive shared owns borrows Hoare Logic Logics C Precondition Postcondition Program Given Box::new(1) {x ↦ 1} {(x ↦ 1) ∗ (y ↦ 1)} *x += *y {(x ↦ 2) ∗ (y ↦ 1)} {x ↦ −} drop(x) {True} Separation Logic (Iris) Type System of λRust (selective) Rust Semantics λRust Type Rust Type bool

的前一个字节被填满了 0 ，根据补码的 规则他是一个正数 128 。 实验：自动类型提升（ type promotion ） • 一个较小类型的 short 和较大类型的 int 相加会得到什么类型？会得到 int 类型。 • 结论：小类型和大类型做数学运算（ +-*/% ）会得到两个类型中的大类型。 实验：自动类型提升（ type promotion ） • 对 unsigned 类型也是同理的。 • int + unsigned short = unsigned int 实验：自动类型提升（ type promotion ） • 如果两边有一边是 unsigned 的但是大小不等，则还是选择较大类型。 • unsigned short + int = int 实验：自动类型提升（ type promotion ） • 如果两边有一边是 unsigned 的但是大小相等，则结果是 unsigned 如果想要的是任意类型的数组呢？ • C 语言中可以用 malloc 和 free 函数来分配动态数 组。 • C++ 则可以用 new 和 delete 来分配动态数组。 • ( 类型 *)malloc( 数组长度 * sizeof( 类型 )) • new 类型 [ 数组长度 ] • 可见 C++ 版本更加简洁了，不需要乘以 sizeof( 类 型 ) 。 • 不过要注意释放的时候必须用

let_[value|…](sender, fn) → sender … passes the result of input sender to function, which returns new sender. when_all(senders...) → sender … completes when all the input senders complete. on(scheduler synchronization is required.44 SENDERS AS AWAITABLES Most senders can be made awaitable in a coroutine type trivially. // This is a coroutine: unifex::task read_socket_async(socket, span); task type: template< class T > struct task { struct promise_type : std::execution::with_awaitable_senderstype> { /*...*/ To make senders awaitable within a coroutine type, derive

WebAssembly 调用本机代码的通信 (messaging) 和 错误处理 (error handling) 。 什么是 waPC? WASM 外部函数 接口 FFI Input type Return type Platform 底层 I32 I32 Unknown waPC &[u8] Result,error > Linux x86_64, macOS x86_64 -> CallResult { let mut req = foo_unmarshall::(msg)?; let re = Regex::new(r”/v2/matches/([a-zA-Z0-9_-]+)/info").unwrap(); if let Some(cap) = re.captures(&req.HttpPath){ “http://$MockServer: $Port/call/$Operation?targets=\/v2\/m atches\/.*\/info" \ --header "Content-Type:application/octet- stream" \ --data-binary "@target/wasm32- unknown-unknown/release/examples/ $3