{"id":7482,"date":"2026-07-24T13:03:14","date_gmt":"2026-07-24T05:03:14","guid":{"rendered":"https:\/\/i007.cc\/wordpress\/?p=7482"},"modified":"2026-07-24T13:03:14","modified_gmt":"2026-07-24T05:03:14","slug":"%e8%af%a6%e8%a7%a3c20%e7%9a%84%e5%8d%8f%e7%a8%8b","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/7482","title":{"rendered":"\u8be6\u89e3C++20\u7684\u534f\u7a0b"},"content":{"rendered":"
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C++20 \u534f\u7a0b\u662f\u6807\u51c6\u91cc\u6700\u590d\u6742\u7684\u7279\u6027\u4e4b\u4e00\uff0c\u8bbe\u8ba1\u76ee\u6807\u662f”\u96f6\u5f00\u9500\u53ef\u5b9a\u5236”\uff0c\u4ee3\u4ef7\u662f\u5b66\u4e60\u66f2\u7ebf\u6781\u9661\u3002\u4e0b\u9762\u4ece\u5e95\u5c42\u673a\u5236\u5230\u5b9e\u9645\u7528\u6cd5\u7cfb\u7edf\u8bb2\u6e05\u695a\u3002<\/p>\n

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\u4e00\u3001\u4ec0\u4e48\u662f C++20 \u534f\u7a0b<\/h3>\n

C++20 \u7684\u534f\u7a0b\u662f\u65e0\u6808\u534f\u7a0b<\/strong>\uff08stackless coroutine\uff09\u3002\u533a\u522b\u5728\u4e8e\uff1a<\/p>\n

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  • \u6709\u6808\u534f\u7a0b<\/strong>\uff08\u5982 Boost.Coroutine\u3001goroutine\uff09\uff1a\u6bcf\u4e2a\u534f\u7a0b\u6709\u81ea\u5df1\u7684\u8c03\u7528\u6808\uff0c\u53ef\u4ee5\u5728\u4efb\u610f\u6df1\u5ea6\u7684\u51fd\u6570\u8c03\u7528\u4e2d\u95f4\u6682\u505c<\/li>\n
  • \u65e0\u6808\u534f\u7a0b<\/strong>\uff1a\u6682\u505c\u70b9\u53ea\u80fd\u51fa\u73b0\u5728\u534f\u7a0b\u51fd\u6570\u672c\u8eab\u7684\u9876\u5c42\uff0c\u5c40\u90e8\u53d8\u91cf\u4fdd\u5b58\u5728\u5806\u4e0a\u7684\u534f\u7a0b\u5e27<\/strong>\u91cc\uff0c\u6ca1\u6709\u72ec\u7acb\u8c03\u7528\u6808<\/li>\n<\/ul>\n

    \u65e0\u6808\u534f\u7a0b\u7684\u5185\u5b58\u5f00\u9500\u8fdc\u5c0f\u4e8e\u6709\u6808\u534f\u7a0b\uff08\u901a\u5e38\u51e0\u5341\u5b57\u8282 vs \u6570 KB\uff09\uff0c\u4f46\u8868\u8fbe\u80fd\u529b\u7a0d\u6709\u9650\u5236\u3002<\/p>\n

    \u4e00\u4e2a\u51fd\u6570\u53ea\u8981\u7528\u4e86\u00a0co_await<\/code>\u3001co_yield<\/code>\u3001co_return<\/code>\u00a0\u4e09\u4e2a\u5173\u952e\u5b57\u4e4b\u4e00\uff0c\u5b83\u5c31\u662f\u534f\u7a0b\u3002<\/p>\n

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    \u4e8c\u3001\u4e09\u4e2a\u5173\u952e\u5b57<\/h3>\n
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    <\/div>\n<\/div>\n
    cpp<\/div>\n
    \n
    co_await expr;    \/\/ \u6682\u505c\u534f\u7a0b\uff0c\u7b49\u5f85 expr \u5b8c\u6210\r\nco_yield value;   \/\/ \u6682\u505c\u534f\u7a0b\uff0c\u5411\u8c03\u7528\u8005\u4ea7\u51fa\u4e00\u4e2a\u503c\r\nco_return value;  \/\/ \u7ed3\u675f\u534f\u7a0b\uff0c\u8fd4\u56de\u6700\u7ec8\u7ed3\u679c<\/pre>\n
     <\/p>\n<\/div>\n<\/div>\n
    \u6ce8\u610f\uff1a\u534f\u7a0b\u51fd\u6570\u7684\u8fd4\u56de\u7c7b\u578b\u4e0d\u662f<\/strong>\u00a0int<\/code>\u3001string<\/code>\u00a0\u8fd9\u7c7b\u666e\u901a\u7c7b\u578b\uff0c\u800c\u662f\u4e00\u4e2a\u7279\u6b8a\u7684 Promise \u7c7b\u578b<\/strong>\uff08\u4e0b\u6587\u8be6\u89e3\uff09\u3002<\/p>\n
    \n
    \u4e09\u3001\u7f16\u8bd1\u5668\u505a\u4e86\u4ec0\u4e48<\/h3>\n
    \u8fd9\u662f\u7406\u89e3 C++20 \u534f\u7a0b\u7684\u5173\u952e\u3002\u5f53\u4f60\u5199\u4e0b\u4e00\u4e2a\u534f\u7a0b\u51fd\u6570\uff0c\u7f16\u8bd1\u5668\u4f1a\u628a\u5b83\u53d8\u6362\u6210\u5927\u91cf”\u770b\u4e0d\u89c1”\u7684\u4ee3\u7801\u3002<\/p>\n
    \u5047\u8bbe\u4f60\u5199\uff1a<\/p>\n
    \n
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    <\/div>\n<\/div>\n
    cpp<\/div>\n
    \n
    Task<int> compute() {\r\n    int x = co_await fetch_data();\r\n    co_return x * 2;\r\n}<\/pre>\n
     <\/p>\n<\/div>\n<\/div>\n
    \u7f16\u8bd1\u5668\u5927\u81f4\u4f1a\u628a\u5b83\u53d8\u6362\u6210\uff1a<\/p>\n
    \n
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    <\/div>\n<\/div>\n
    cpp<\/div>\n
    \n
    \/\/ \u4f2a\u4ee3\u7801\uff0c\u5c55\u793a\u7f16\u8bd1\u5668\u7684\u53d8\u6362\u903b\u8f91\r\nTask<int> compute() {\r\n    \/\/ 1. \u5728\u5806\u4e0a\u5206\u914d\u534f\u7a0b\u5e27\uff0c\u5b58\u653e\u5c40\u90e8\u53d8\u91cf\u548c\u6682\u505c\u72b6\u6001\r\n    auto* frame = operator new(sizeof(ComputeFrame));\r\n    \r\n    \/\/ 2. \u6784\u9020 promise \u5bf9\u8c61\uff08\u4f4d\u4e8e\u534f\u7a0b\u5e27\u5185\uff09\r\n    promise_type promise;\r\n    \r\n    \/\/ 3. \u62ff\u5230\u8fd4\u56de\u7ed9\u8c03\u7528\u8005\u7684\u5bf9\u8c61\r\n    Task<int> result = promise.get_return_object();\r\n    \r\n    \/\/ 4. \u6267\u884c\u521d\u59cb\u6682\u505c\uff08\u5982\u679c initial_suspend \u8fd4\u56de suspend_always\uff09\r\n    co_await promise.initial_suspend();\r\n    \r\n    \/\/ ---- \u534f\u7a0b\u4f53\u5f00\u59cb ----\r\n    int x = co_await fetch_data();   \/\/ \u6682\u505c\u70b9\r\n    promise.return_value(x * 2);     \/\/ co_return \u5c55\u5f00\r\n    \/\/ ---- \u534f\u7a0b\u4f53\u7ed3\u675f ----\r\n    \r\n    \/\/ 5. \u6267\u884c\u6700\u7ec8\u6682\u505c\r\n    co_await promise.final_suspend();\r\n    \r\n    \/\/ 6. \u9500\u6bc1\u534f\u7a0b\u5e27\r\n    frame->destroy();\r\n    \r\n    return result;\r\n}<\/pre>\n
     <\/p>\n<\/div>\n<\/div>\n
    \u5173\u952e\u5728\u4e8e\uff1aresult<\/code>\u00a0\u5728\u6b65\u9aa4 3 \u5c31\u8fd4\u56de\u7ed9\u8c03\u7528\u8005\u4e86\uff0c\u6b64\u65f6\u534f\u7a0b\u4f53\u751a\u81f3\u8fd8\u6ca1\u5f00\u59cb\u6267\u884c\uff08\u53d6\u51b3\u4e8e\u00a0initial_suspend<\/code>\u00a0\u7684\u7b56\u7565\uff09\u3002<\/p>\n
    \n
    \u56db\u3001\u534f\u7a0b\u5e27\uff08Coroutine Frame\uff09<\/h3>\n
    \u6bcf\u4e2a\u534f\u7a0b\u5b9e\u4f8b\u5728\u5806\u4e0a\u6709\u4e00\u4e2a\u534f\u7a0b\u5e27<\/strong>\uff0c\u5305\u542b\uff1a<\/p>\n
      \n
    • \u6240\u6709\u5c40\u90e8\u53d8\u91cf\uff08\u5728\u6682\u505c\u70b9\u4e4b\u95f4\u5b58\u6d3b\u7684\u90a3\u4e9b\uff09<\/li>\n
    • promise_type<\/code>\u00a0\u5bf9\u8c61<\/li>\n
    • \u5f53\u524d\u6682\u505c\u70b9\u7684\u7d22\u5f15\uff08\u5b9e\u73b0\u4e3a\u4e00\u4e2a\u72b6\u6001\u673a\uff09<\/li>\n
    • \u534f\u7a0b\u51fd\u6570\u7684\u53c2\u6570\u526f\u672c<\/li>\n<\/ul>\n
      \u7f16\u8bd1\u5668\u4f1a\u628a\u534f\u7a0b\u4f53\u53d8\u6210\u4e00\u4e2a\u72b6\u6001\u673a<\/strong>\uff0c\u6bcf\u6b21\u00a0resume()<\/code>\u00a0\u4ece\u4e0a\u6b21\u6682\u505c\u7684\u5730\u65b9\u7ee7\u7eed\u6267\u884c\uff1a<\/p>\n
      \n
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      <\/div>\n<\/div>\n
      \n
      \u72b6\u6001 0 \u2192 \u6267\u884c\u5230 co_await fetch_data() \u2192 \u6682\u505c \u2192 \u72b6\u6001 1\r\n\u72b6\u6001 1 \u2192 fetch_data() \u5b8c\u6210\uff0cresume() \u88ab\u8c03\u7528 \u2192 \u6267\u884c co_return \u2192 \u72b6\u6001 2 (done)<\/pre>\n
       <\/p>\n<\/div>\n<\/div>\n
      \n
      \u4e94\u3001\u56db\u4e2a\u6838\u5fc3\u5b9a\u5236\u70b9<\/h3>\n
      C++20 \u534f\u7a0b\u7684”\u590d\u6742”\u4e3b\u8981\u6765\u81ea\u8fd9\u91cc\u2014\u2014\u6807\u51c6\u53ea\u63d0\u4f9b\u673a\u5236\uff0c\u4e0d\u63d0\u4f9b\u7b56\u7565\uff0c\u6240\u6709\u884c\u4e3a\u90fd\u901a\u8fc7\u8fd9\u56db\u4e2a\u4e1c\u897f\u5b9a\u5236\u3002<\/p>\n
      1. Promise \u7c7b\u578b\uff08promise_type<\/code>\uff09<\/h4>\n
      \u534f\u7a0b\u7684\u8fd4\u56de\u7c7b\u578b\u00a0T<\/code>\u00a0\u5fc5\u987b\u6709\u4e00\u4e2a\u5d4c\u5957\u7c7b\u578b\u00a0T::promise_type<\/code>\uff08\u6216\u901a\u8fc7\u00a0coroutine_traits<\/code>\u00a0\u7279\u5316\u6307\u5b9a\uff09\uff0c\u5b83\u63a7\u5236\u534f\u7a0b\u7684\u751f\u547d\u5468\u671f\u884c\u4e3a\uff1a<\/p>\n
      \n
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      <\/div>\n<\/div>\n
      cpp<\/div>\n
      \n
      struct MyPromise {\r\n    \/\/ \u5fc5\u987b\uff1a\u8fd4\u56de\u7ed9\u8c03\u7528\u8005\u7684\u5bf9\u8c61\r\n    Task<int> get_return_object();\r\n    \r\n    \/\/ \u5fc5\u987b\uff1a\u534f\u7a0b\u521a\u521b\u5efa\u65f6\u662f\u5426\u7acb\u5373\u6682\u505c\r\n    \/\/ suspend_always \u2192 \u61d2\u542f\u52a8\uff1bsuspend_never \u2192 \u7acb\u5373\u5f00\u59cb\u6267\u884c\r\n    auto initial_suspend() { return std::suspend_always{}; }\r\n    \r\n    \/\/ \u5fc5\u987b\uff1a\u534f\u7a0b\u7ed3\u675f\u65f6\u662f\u5426\u6682\u505c\uff08\u63a7\u5236\u8c01\u9500\u6bc1\u534f\u7a0b\u5e27\uff09\r\n    auto final_suspend() noexcept { return std::suspend_always{}; }\r\n    \r\n    \/\/ \u5fc5\u987b\uff1a\u5904\u7406\u672a\u6355\u83b7\u5f02\u5e38\r\n    void unhandled_exception() { std::terminate(); }\r\n    \r\n    \/\/ co_return value \u65f6\u8c03\u7528\r\n    void return_value(int v) { result = v; }\r\n    \r\n    \/\/ co_yield value \u65f6\u8c03\u7528\uff08\u8fd4\u56de\u4e00\u4e2a awaitable\uff09\r\n    auto yield_value(int v) { \r\n        result = v; \r\n        return std::suspend_always{}; \r\n    }\r\n    \r\n    int result;\r\n};<\/pre>\n
       <\/p>\n<\/div>\n<\/div>\n
      2. Awaitable \u4e0e Awaiter<\/h4>\n
      co_await expr<\/code>\u00a0\u4e2d\u7684\u00a0expr<\/code>\u00a0\u5fc5\u987b\u662f\u4e00\u4e2a\u00a0Awaitable<\/strong>\u3002\u7f16\u8bd1\u5668\u4f1a\u628a\u5b83\u53d8\u6362\u6210\uff1a<\/p>\n
      \n
      \n
      <\/div>\n<\/div>\n
      cpp<\/div>\n
      \n
      auto&& awaitable = expr;\r\n\r\n\/\/ \u5148\u5c1d\u8bd5\u4ece awaitable \u83b7\u53d6 awaiter\uff08\u53ef\u4ee5\u662f awaitable \u81ea\u8eab\uff09\r\nauto&& awaiter = awaitable.operator co_await();\r\n\/\/ \u6216\u8005 operator co_await(awaitable)\r\n\r\n\/\/ \u7136\u540e\u6267\u884c\u4e09\u6b65\u534f\u8bae\uff1a\r\nif (!awaiter.await_ready()) {           \/\/ \u662f\u5426\u5df2\u7ecf\u5c31\u7eea\uff1f\r\n    awaiter.await_suspend(handle);      \/\/ \u6682\u505c\uff0chandle \u662f\u5f53\u524d\u534f\u7a0b\u7684\u53e5\u67c4\r\n    \/\/ ... \u63a7\u5236\u6743\u8fd4\u56de\u7ed9\u8c03\u7528\u8005 ...\r\n}\r\nauto result = awaiter.await_resume();   \/\/ \u6062\u590d\u65f6\u62ff\u5230\u7ed3\u679c<\/pre>\n
       <\/p>\n<\/div>\n<\/div>\n
      \u6240\u4ee5\u81ea\u5b9a\u4e49 awaiter \u9700\u8981\u5b9e\u73b0\u4e09\u4e2a\u65b9\u6cd5\uff1a<\/p>\n
      \n
      \n
      <\/div>\n<\/div>\n
      cpp<\/div>\n
      \n
      struct MyAwaiter {\r\n    bool await_ready() { return false; }  \/\/ false = \u9700\u8981\u6682\u505c\r\n    \r\n    void await_suspend(std::coroutine_handle<> handle) {\r\n        \/\/ \u5728\u8fd9\u91cc\uff1a\u628a handle \u4ea4\u7ed9\u67d0\u4e2a\u5f02\u6b65\u64cd\u4f5c\r\n        \/\/ \u5f53\u5f02\u6b65\u64cd\u4f5c\u5b8c\u6210\u65f6\uff0c\u8c03\u7528 handle.resume() \u6062\u590d\u534f\u7a0b\r\n        async_op.on_complete([handle]{ handle.resume(); });\r\n    }\r\n    \r\n    int await_resume() { return result; }  \/\/ \u6682\u505c\u7ed3\u675f\u540e\u7684\u8fd4\u56de\u503c\r\n    \r\n    int result;\r\n};<\/pre>\n
       <\/p>\n<\/div>\n<\/div>\n
      await_suspend<\/code>\u00a0\u8fd8\u53ef\u4ee5\u8fd4\u56de\u00a0bool<\/code>\uff08false \u5219\u4e0d\u6682\u505c\uff09\u6216\u53e6\u4e00\u4e2a\u00a0coroutine_handle<><\/code>\uff08\u5bf9\u79f0\u8f6c\u79fb\uff0c\u907f\u514d\u6808\u6ea2\u51fa\uff09\u3002<\/p>\n
      3.\u00a0coroutine_handle<P><\/code><\/h4>\n
      std::coroutine_handle<P><\/code>\u00a0\u662f\u534f\u7a0b\u7684\u53e5\u67c4<\/strong>\uff0c\u672c\u8d28\u4e0a\u662f\u6307\u5411\u534f\u7a0b\u5e27\u7684\u6307\u9488\u3002\u5b83\u7684\u6838\u5fc3\u64cd\u4f5c\uff1a<\/p>\n
      \n
      \n
      <\/div>\n<\/div>\n
      cpp<\/div>\n
      \n
      handle.resume();   \/\/ \u6062\u590d\u534f\u7a0b\u6267\u884c\r\nhandle.destroy();  \/\/ \u9500\u6bc1\u534f\u7a0b\u5e27\uff0c\u91ca\u653e\u5185\u5b58\r\nhandle.done();     \/\/ \u662f\u5426\u5df2\u7ecf\u7ed3\u675f\r\nhandle.promise();  \/\/ \u8bbf\u95ee promise \u5bf9\u8c61<\/pre>\n
       <\/p>\n<\/div>\n<\/div>\n
      coroutine_handle<void><\/code>\u00a0\u662f\u7c7b\u578b\u64e6\u9664\u7248\u672c\uff0c\u53ef\u4ee5\u6307\u5411\u4efb\u4f55\u534f\u7a0b\u3002<\/p>\n
      4.\u00a0std::suspend_always<\/code>\u00a0\u548c\u00a0std::suspend_never<\/code><\/h4>\n
      \u8fd9\u4e24\u4e2a\u662f\u6807\u51c6\u63d0\u4f9b\u7684\u6700\u7b80\u5355\u7684 awaiter\uff1a<\/p>\n
      \n
      \n
      <\/div>\n<\/div>\n
      cpp<\/div>\n
      \n
      struct suspend_always {\r\n    bool await_ready() { return false; }   \/\/ \u603b\u662f\u6682\u505c\r\n    void await_suspend(coroutine_handle<>) {}\r\n    void await_resume() {}\r\n};\r\n\r\nstruct suspend_never {\r\n    bool await_ready() { return true; }    \/\/ \u4ece\u4e0d\u6682\u505c\r\n    void await_suspend(coroutine_handle<>) {}\r\n    void await_resume() {}\r\n};<\/pre>\n
       <\/p>\n<\/div>\n<\/div>\n
      \n
      \u516d\u3001\u4ece\u96f6\u5b9e\u73b0\u4e00\u4e2a Generator<\/h3>\n
      \u7528\u534f\u7a0b\u5b9e\u73b0\u60f0\u6027\u5e8f\u5217\u751f\u6210\u5668\uff0c\u662f\u6700\u76f4\u89c2\u7684\u5165\u95e8\u6848\u4f8b\uff1a<\/p>\n
      \n
      \n
      <\/div>\n<\/div>\n
      cpp<\/div>\n
      \n
      #include <coroutine>\r\n#include <optional>\r\n\r\ntemplate<typename T>\r\nclass Generator {\r\npublic:\r\n    struct promise_type {\r\n        std::optional<T> value;\r\n        \r\n        Generator get_return_object() {\r\n            return Generator{Handle::from_promise(*this)};\r\n        }\r\n        std::suspend_always initial_suspend() { return {}; }\r\n        std::suspend_always final_suspend() noexcept { return {}; }\r\n        void unhandled_exception() { std::terminate(); }\r\n        void return_void() {}\r\n        \r\n        std::suspend_always yield_value(T v) {\r\n            value = std::move(v);\r\n            return {};\r\n        }\r\n    };\r\n    \r\n    using Handle = std::coroutine_handle<promise_type>;\r\n    \r\n    explicit Generator(Handle h) : handle(h) {}\r\n    ~Generator() { if (handle) handle.destroy(); }\r\n    \r\n    \/\/ \u4e0d\u53ef\u62f7\u8d1d\uff0c\u53ef\u79fb\u52a8\r\n    Generator(const Generator&) = delete;\r\n    Generator(Generator&& o) : handle(o.handle) { o.handle = {}; }\r\n    \r\n    std::optional<T> next() {\r\n        if (!handle || handle.done()) return std::nullopt;\r\n        handle.resume();\r\n        if (handle.done()) return std::nullopt;\r\n        return handle.promise().value;\r\n    }\r\n\r\nprivate:\r\n    Handle handle;\r\n};\r\n\r\n\/\/ \u4f7f\u7528\uff1a\r\nGenerator<int> fibonacci() {\r\n    int a = 0, b = 1;\r\n    while (true) {\r\n        co_yield a;\r\n        auto c = a + b;\r\n        a = b;\r\n        b = c;\r\n    }\r\n}\r\n\r\nint main() {\r\n    auto gen = fibonacci();\r\n    for (int i = 0; i < 10; i++) {\r\n        std::cout << *gen.next() << \" \";\r\n    }\r\n    \/\/ \u8f93\u51fa: 0 1 1 2 3 5 8 13 21 34\r\n}<\/pre>\n
       <\/p>\n<\/div>\n<\/div>\n
      \n
      \u4e03\u3001\u5f02\u6b65\u4efb\u52a1\uff1a\u5b9e\u73b0 Task<\/h3>\n
      \u5f02\u6b65\u573a\u666f\u4e0b\uff0cTask<T><\/code>\u00a0\u8868\u793a\u4e00\u4e2a\u61d2\u542f\u52a8\u7684\u5355\u6b21\u5f02\u6b65\u64cd\u4f5c\uff1a<\/p>\n
      \n
      \n
      <\/div>\n<\/div>\n
      cpp<\/div>\n
      \n
      template<typename T>\r\nclass Task {\r\npublic:\r\n    struct promise_type {\r\n        std::variant<std::monostate, T, std::exception_ptr> result;\r\n        std::coroutine_handle<> continuation;  \/\/ \u7b49\u5f85\u6211\u7684\u90a3\u4e2a\u534f\u7a0b\r\n        \r\n        Task get_return_object() {\r\n            return Task{Handle::from_promise(*this)};\r\n        }\r\n        \r\n        \/\/ \u61d2\u542f\u52a8\uff1a\u521b\u5efa\u540e\u4e0d\u7acb\u5373\u6267\u884c\r\n        std::suspend_always initial_suspend() { return {}; }\r\n        \r\n        \/\/ \u7ed3\u675f\u65f6\u6682\u505c\uff0c\u7136\u540e\u6062\u590d\u7b49\u5f85\u8005\r\n        auto final_suspend() noexcept {\r\n            struct FinalAwaiter {\r\n                bool await_ready() noexcept { return false; }\r\n                auto await_suspend(Handle h) noexcept {\r\n                    \/\/ \u5bf9\u79f0\u8f6c\u79fb\uff1a\u76f4\u63a5\u8df3\u8f6c\u5230 continuation\uff0c\u4e0d\u589e\u52a0\u8c03\u7528\u6808\r\n                    return h.promise().continuation;\r\n                }\r\n                void await_resume() noexcept {}\r\n            };\r\n            return FinalAwaiter{};\r\n        }\r\n        \r\n        void return_value(T v) { result = std::move(v); }\r\n        void unhandled_exception() { result = std::current_exception(); }\r\n    };\r\n    \r\n    using Handle = std::coroutine_handle<promise_type>;\r\n    \r\n    \/\/ Task \u672c\u8eab\u662f\u4e00\u4e2a Awaitable\r\n    bool await_ready() { return false; }\r\n    \r\n    auto await_suspend(std::coroutine_handle<> caller) {\r\n        handle.promise().continuation = caller;\r\n        return handle;  \/\/ \u5bf9\u79f0\u8f6c\u79fb\u5230 task \u7684\u534f\u7a0b\r\n    }\r\n    \r\n    T await_resume() {\r\n        auto& result = handle.promise().result;\r\n        if (std::holds_alternative<std::exception_ptr>(result))\r\n            std::rethrow_exception(std::get<std::exception_ptr>(result));\r\n        return std::move(std::get<T>(result));\r\n    }\r\n    \r\n    \/\/ ... \u6784\u9020\u3001\u6790\u6784\u3001\u79fb\u52a8\u8bed\u4e49\u7701\u7565 ...\r\n    \r\nprivate:\r\n    Handle handle;\r\n};\r\n\r\n\/\/ \u4f7f\u7528\uff1a\r\nTask<int> fetch_user_id(std::string name) {\r\n    auto data = co_await http_get(\"\/users\/\" + name);\r\n    co_return data[\"id\"].as<int>();\r\n}\r\n\r\nTask<std::string> get_username() {\r\n    int id = co_await fetch_user_id(\"alice\");\r\n    auto info = co_await http_get(\"\/profiles\/\" + std::to_string(id));\r\n    co_return info[\"name\"].as<std::string>();\r\n}<\/pre>\n
       <\/p>\n<\/div>\n<\/div>\n
      \n
      \u516b\u3001\u5bf9\u79f0\u8f6c\u79fb\uff08Symmetric Transfer\uff09<\/h3>\n
      \u8fd9\u662f C++20 \u534f\u7a0b\u7684\u4e00\u4e2a\u5173\u952e\u6280\u672f\u7ec6\u8282\uff0c\u89e3\u51b3\u7684\u662f\u6808\u6ea2\u51fa\u95ee\u9898\u3002<\/p>\n
      \u6ca1\u6709\u5bf9\u79f0\u8f6c\u79fb\u65f6\uff1a<\/p>\n
      \n
      \n
      <\/div>\n<\/div>\n
      \n
      main \u2192 resume(task_A) \u2192 task_A \u7ed3\u675f \u2192 resume(task_B) \u2192 task_B \u7ed3\u675f \u2192 ...<\/pre>\n
       <\/p>\n<\/div>\n<\/div>\n
      \u6bcf\u6b21\u00a0resume<\/code>\u00a0\u90fd\u662f\u4e00\u6b21\u51fd\u6570\u8c03\u7528\uff0c\u94fe\u5f0f\u8c03\u7528\u4f1a\u6491\u7206\u8c03\u7528\u6808\u3002<\/p>\n
      await_suspend<\/code>\u00a0\u8fd4\u56de\u00a0coroutine_handle<><\/code>\u00a0\u65f6\uff0c\u7f16\u8bd1\u5668\u4f1a\u628a\u5b83\u53d8\u6210”\u5c3e\u8c03\u7528\u8df3\u8f6c”\uff1a<\/p>\n
      \n
      \n
      <\/div>\n<\/div>\n
      cpp<\/div>\n
      \n
      auto await_suspend(coroutine_handle<> h) -> coroutine_handle<> {\r\n    return next_coro;  \/\/ \u76f4\u63a5\u8df3\u8f6c\uff0c\u4e0d\u589e\u52a0\u6808\u5e27\r\n}<\/pre>\n
       <\/p>\n<\/div>\n<\/div>\n
      \u8fd9\u662f C++20 \u534f\u7a0b\u80fd\u9ad8\u6548\u5b9e\u73b0 continuation-passing style \u7684\u57fa\u7840\u3002<\/p>\n
      \n
      \u4e5d\u3001\u5185\u5b58\u5206\u914d\u4f18\u5316<\/h3>\n
      \u534f\u7a0b\u5e27\u9ed8\u8ba4\u7528\u00a0operator new<\/code>\u00a0\u5206\u914d\u3002\u4f46\u7f16\u8bd1\u5668\u6709\u4e00\u4e2a\u91cd\u8981\u4f18\u5316\uff1a\u534f\u7a0b\u5e27\u7701\u7565<\/strong>\uff08Heap Allocation Elision Optimization, HALO\uff09\u2014\u2014\u5982\u679c\u7f16\u8bd1\u5668\u80fd\u786e\u5b9a\u534f\u7a0b\u7684\u751f\u547d\u5468\u671f\u4e0d\u8d85\u8fc7\u8c03\u7528\u8005\uff0c\u5b83\u53ef\u4ee5\u628a\u534f\u7a0b\u5e27\u5206\u914d\u5728\u8c03\u7528\u8005\u7684\u6808\u4e0a\uff0c\u5f7b\u5e95\u6d88\u9664\u5806\u5206\u914d\u3002<\/p>\n
      \u8fd9\u4e2a\u4f18\u5316\u5728\u5b9e\u8df5\u4e2d\u5e38\u89c1\u4e8e\u7b80\u5355\u7684 generator \u573a\u666f\uff0c\u4f46\u5728\u8de8\u8d8a\u5f02\u6b65\u8fb9\u754c\u65f6\u901a\u5e38\u65e0\u6cd5\u89e6\u53d1\u3002<\/p>\n
      \u81ea\u5b9a\u4e49\u5206\u914d\u53ef\u4ee5\u5728\u00a0promise_type<\/code>\u00a0\u91cc\u91cd\u8f7d\u00a0operator new<\/code>\uff1a<\/p>\n
      \n
      \n
      <\/div>\n<\/div>\n
      cpp<\/div>\n
      \n
      struct promise_type {\r\n    void* operator new(size_t size, MyAllocator& alloc, ...) {\r\n        return alloc.allocate(size);\r\n    }\r\n    void operator delete(void* ptr, size_t size) {\r\n        MyAllocator::deallocate(ptr, size);\r\n    }\r\n};<\/pre>\n
       <\/p>\n<\/div>\n<\/div>\n
      \n
      \u5341\u3001\u6807\u51c6\u5e93\u63d0\u4f9b\u4e86\u4ec0\u4e48\uff0c\u6ca1\u63d0\u4f9b\u4ec0\u4e48<\/h3>\n
      \u63d0\u4f9b\u4e86\uff1a<\/strong><\/p>\n
        \n
      • std::coroutine_handle<P><\/code>\u00a0\u2014 \u534f\u7a0b\u53e5\u67c4<\/li>\n
      • std::coroutine_traits<R, Args...><\/code>\u00a0\u2014 \u5b9a\u5236 promise_type \u7684\u7279\u5316\u70b9<\/li>\n
      • std::suspend_always<\/code>\u3001std::suspend_never<\/code>\u00a0\u2014 \u4e24\u4e2a\u57fa\u7840 awaiter<\/li>\n
      • std::noop_coroutine()<\/code>\u00a0\u2014 \u7528\u4e8e\u5bf9\u79f0\u8f6c\u79fb\u94fe\u7684\u7ec8\u6b62\u8282\u70b9<\/li>\n<\/ul>\n
        \u6ca1\u6709\u63d0\u4f9b\uff1a<\/strong><\/p>\n
          \n
        • Task<T><\/code>\u3001Generator<T><\/code>\u3001AsyncGenerator<T><\/code>\u00a0\u2014 \u4f60\u8981\u81ea\u5df1\u5199\u6216\u7528\u5e93<\/li>\n
        • \u7ebf\u7a0b\u6c60\u8c03\u5ea6\u5668<\/li>\n
        • \u4efb\u4f55\u5f02\u6b65 I\/O \u96c6\u6210<\/li>\n<\/ul>\n
          \u8fd9\u662f C++20 \u534f\u7a0b\u88ab\u8bdf\u75c5\u6700\u591a\u7684\u4e00\u70b9\uff1a\u6807\u51c6\u53ea\u7ed9\u4e86\u673a\u5236<\/strong>\uff0c\u6ca1\u7ed9\u5de5\u5177<\/strong>\u3002\u4f60\u62ff\u5230\u7684\u662f\u53d1\u52a8\u673a\u96f6\u4ef6\uff0c\u4e0d\u662f\u4e00\u8f86\u8f66\u3002<\/p>\n
          \n
          \u5341\u4e00\u3001\u5b9e\u9645\u4e0a\u7528\u4ec0\u4e48<\/h3>\n
          \u624b\u5199\u00a0Task<\/code>\/Generator<\/code>\u00a0\u975e\u5e38\u7e41\u7410\u4e14\u5bb9\u6613\u51fa\u9519\uff0c\u5b9e\u9645\u9879\u76ee\u4e2d\u901a\u5e38\u7528\uff1a<\/p>\n
            \n
          • cppcoro<\/strong>\uff08Lewis Baker \u5199\u7684\uff0c\u662f P2300 \u7684\u7cbe\u795e\u524d\u8eab\uff0c\u5df2\u505c\u6b62\u7ef4\u62a4\u4f46\u4ee3\u7801\u8d28\u91cf\u6781\u9ad8\uff0c\u503c\u5f97\u5b66\u4e60\uff09<\/li>\n
          • libunifex<\/strong>\uff08Meta\uff0cP2300 \u7684\u53e6\u4e00\u4e2a\u53c2\u8003\u5b9e\u73b0\uff0c\u4e0e sender\/receiver \u96c6\u6210\uff09<\/li>\n
          • Asio<\/strong>\uff08Boost.Asio \u548c standalone Asio \u90fd\u652f\u6301\u00a0co_await<\/code>\uff0c\u662f\u76ee\u524d\u751f\u4ea7\u53ef\u7528\u5ea6\u6700\u9ad8\u7684\u9009\u9879\uff09<\/li>\n
          • cpptask \/ folly::coro<\/strong>\uff08Facebook \u5185\u90e8\uff0c\u6709\u5f00\u6e90\u7248\uff09<\/li>\n
          • C++26 \u7684\u00a0std::generator<\/code><\/strong>\uff08\u6807\u51c6\u7ec8\u4e8e\u63d0\u4f9b\u4e86\u4e00\u4e2a generator\uff0c\u4e0d\u8fc7\u53ea\u662f C++26\uff09<\/li>\n<\/ul>\n
            \n
            \u5341\u4e8c\u3001\u4e0e Rust async\/await \u7684\u5bf9\u6bd4<\/h3>\n
            \n\n\n\n\n\n\n\n\n\n\n\n
            <\/th>\nC++20 \u534f\u7a0b<\/th>\nRust async\/await<\/th>\n<\/tr>\n<\/thead>\n
            \u534f\u7a0b\u7c7b\u578b<\/td>\n\u65e0\u6808<\/td>\n\u65e0\u6808<\/td>\n<\/tr>\n
            \u8fd0\u884c\u65f6<\/td>\n\u65e0\u5185\u7f6e\u8fd0\u884c\u65f6\uff0c\u5b8c\u5168\u5b9a\u5236<\/td>\n\u65e0\u5185\u7f6e\u8fd0\u884c\u65f6\uff0c\u9700\u8981 tokio\/async-std<\/td>\n<\/tr>\n
            \u5f00\u9500<\/td>\n\u7406\u8bba\u96f6\u5f00\u9500\uff0c\u5b9e\u8df5\u4e2d\u53d6\u51b3\u4e8e\u5b9e\u73b0<\/td>\n\u7c7b\u4f3c<\/td>\n<\/tr>\n
            \u5b66\u4e60\u66f2\u7ebf<\/td>\n\u6781\u9661\uff0c\u9700\u7406\u89e3 promise\/awaiter \u534f\u8bae<\/td>\n\u8f83\u5e73\uff0casync fn \u81ea\u52a8\u63a8\u5bfc Future<\/td>\n<\/tr>\n
            \u751f\u6001<\/td>\n\u788e\u7247\u5316\uff0c\u65e0\u7edf\u4e00 executor<\/td>\ntokio \u4e00\u7edf\u6c5f\u6e56<\/td>\n<\/tr>\n
            \u9519\u8bef\u5904\u7406<\/td>\n\u624b\u52a8\uff0cunhandled_exception<\/code><\/td>\n?<\/code>\u00a0\u8fd0\u7b97\u7b26\u5929\u7136\u652f\u6301<\/td>\n<\/tr>\n
            \u53d6\u6d88<\/td>\n\u65e0\u6807\u51c6\u673a\u5236<\/td>\n\u65e0\u6807\u51c6\u673a\u5236\uff0ctokio \u6709\u00a0CancellationToken<\/code><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
            C++ \u534f\u7a0b\u7684\u5b9a\u5236\u80fd\u529b\u6bd4 Rust \u5f3a\u5f97\u591a\uff08\u4f60\u53ef\u4ee5\u5b8c\u5168\u63a7\u5236\u8c03\u5ea6\u7b56\u7565\u548c\u5185\u5b58\u5206\u914d\uff09\uff0c\u4f46\u8fd9\u79cd\u81ea\u7531\u5ea6\u7684\u4ee3\u4ef7\u662f\u6781\u9ad8\u7684\u590d\u6742\u6027\u3002Rust \u9009\u62e9\u4e86\u4e00\u4e2a\u66f4\u7a84\u4f46\u66f4\u597d\u7528\u7684\u70b9\u3002<\/p>\n
            \n
            \u4e00\u53e5\u8bdd\u603b\u7ed3<\/h3>\n
            C++20 \u534f\u7a0b\u662f\u4e00\u5957\u53ef\u5b9a\u5236\u7684\u7f16\u8bd1\u671f\u53d8\u6362\u673a\u5236<\/strong>\uff0c\u628a\u534f\u7a0b\u51fd\u6570\u53d8\u6210\u72b6\u6001\u673a\uff0c\u628a\u5c40\u90e8\u72b6\u6001\u5b58\u5230\u5806\u4e0a\u7684\u534f\u7a0b\u5e27\u91cc\u3002\u5b83\u672c\u8eab\u6781\u5176\u7075\u6d3b\uff0c\u4f46\u51e0\u4e4e\u4e0d\u63d0\u4f9b\u5f00\u7bb1\u5373\u7528\u7684\u5de5\u5177\u2014\u2014\u771f\u6b63\u62ff\u6765\u7528\u8fd8\u9700\u8981\u4e00\u4e2a\u6210\u719f\u7684\u4e0a\u5c42\u5e93\uff08\u76ee\u524d Asio \u662f\u6700\u73b0\u5b9e\u7684\u9009\u62e9\uff09\uff0c\u6216\u8005\u7b49 C++26\/C++29 \u6807\u51c6\u5e93\u9010\u6b65\u8865\u5168\u914d\u5957\u8bbe\u65bd\u3002<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
            C++20 \u534f\u7a0b\u662f\u6807\u51c6\u91cc\u6700\u590d\u6742\u7684\u7279\u6027\u4e4b\u4e00<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[24],"tags":[],"class_list":["post-7482","post","type-post","status-publish","format-standard","hentry","category-value_docs"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/7482","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=7482"}],"version-history":[{"count":1,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/7482\/revisions"}],"predecessor-version":[{"id":7483,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/7482\/revisions\/7483"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=7482"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=7482"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=7482"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}