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

Support21 Literal Suffix for size_t  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 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)

-> 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){ Example includes handshake, websocket codec, and message modification 模拟数据规则 例子包括握手，数据解析， 更改数据 new Websocket(“ws://localhost:3335") 模拟前 - before 模拟后 - after • Wasm builds a req buffer • If wasm insert(“request”.into(),request); reg.insert(“request_marshalling”.into(),request_marshalli ng); reg.insert(“response_marshalling”.into(),response_marsh alling); } 自动化 HTTP 请求例子 自动化测试以循环方式执行

(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() { While you could just represent these values with unsigned ints or the underlying data, these new calendrical types also provide valuable abstraction. To use weekdays, months, weekday_indexeds

counted_cb old_ccb = cctrl.load(), new_ccb; do { new_ccb = old_ccb; new_ccb.local_ref_count++; } while (!cctrl.compare_exchange(old_ccb , new_ccb)) return new_ccb; } struct counted_cb { control_block* old_ccb = prev_ccb, new_ccb; do { new_ccb = old_ccb; new_ccb.local_ref_count--; } while (old_ccb.ctrl == prev_ccb.ctrl && !cctrl.compare_exchange(old_ccb , new_ccb)) if (old_ccb old_ccb = prev_ccb, new_ccb; do { new_ccb = old_ccb; new_ccb.local_ref_count--; } while (old_ccb.ctrl == prev_ccb.ctrl && !cctrl.compare_exchange(old_ccb , new_ccb)) if (old_ccb

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 Small Standard Library Additions5 Agenda  New keywords:  concept  requires  constinit  consteval  co_await  co_return  co_yield  char8_t  New identifiers:  import  moduleModules7  constexpr functions can now:  use dynamic_cast() and typeid  do dynamic memory allocations, new / delete  contain try/catch blocks  But still cannot throw exceptions33 constexpr string & vector

同学们可以课后研究一下。 第 5 章：内存分配与分页 vector ：写入两次，时间都是一样的（理所当然） malloc ：写入两次，第一次明显比第二次慢？ new int[n] ：和 malloc 一样，写入两次，第一次明显比第二次慢？ new int[n]{} ：后面加个花括号，就和 vector 一样，两次一样快了 结论 • 原理，当调用 malloc 时，操作系统并不会实际分配那一块内存，而是将这一段内存标记 malloc 过的地址，那就说明他确实犯错了，就抛出段错误（ segmentation fault ）。 • std::vector 、 new int[n]{} 会初始化数组为 0 。 • malloc(n * sizeof(int)) 、 new int[n] 不会初始化数组为 0 。 • 初始化数组时，内存被写入，所以操作系统这时候才开始实际分配内存。 • 刚才的案例里，不会初始化的 _mm_prefetch ，也更高效。 标准库的 new 和 malloc ：只保证 16 字节对齐 • 不过其实标准库的 new 和 malloc 已经 可以保证 16 字节对齐了。如果你只需要 用 _mm_load_ps 而不用 _mm256_load_ps 的话，那直接用标准库 的内存分配也没问题。 标准库的 new 和 malloc ：只保证 16 字节对齐 • 还有

Source: https://cacm.acm.org/magazines/2019/2/234352-a- new-golden-age-for-computer-architecture/fulltext Source: https://www.zdnet.com/article/risc-v-the- year-of-growth-and-progress-ratifying-multiple- technical-specifications-launching-new-education-programs-and-accelerating-broad-industry-adoption/  https://riscv.org/blog/2021/06/ Desktop II. Practicing Sparrow  https://www.phoronix.com/scan.php?page=news_item&px=Pop-OS-New-Rust-Desktop Source: https://news.itsfoss.com/system76-rust-cosmic-desktop/ 2.1.2 System76-Scheduler

+ y[i]; } TEST_CASE("cppcon-0", "[CUDA]") { int N = 1 << 20; float* x = new float[N]; float* y = new float[N]; for (int i = 0; i < N; i++) { x[i] = 1.0f; y[i] = 2 Unified Memory System Memory GPU Memory 13 |Memory Allocation // cpu float* x = new float[N]; float* y = new float[N]; // … delete[] x; delete[] y; // gpu float* x; float* y; cudaMallocManaged( std::pmr::polymorphic_allocator { // constructors template void construct(U* p) { ::new (static_cast(p)) U; } }; template using vector = std::vector>;