标准库头文件 <coroutine> (C++20)
来自 cppreference.cn
此头文件是语言支持库的一部分。
包含 | ||
| (C++20) |
三路比较运算符 支持 | |
类 | ||
| (C++20) |
用于发现协程 promise 类型的 trait 类型 (类模板) | |
| (C++20) |
用于指代挂起或正在执行的协程 (类模板) | |
| std::coroutine_handle 的哈希支持 (类模板特化) | ||
空操作协程 | ||
| (C++20) |
用于没有可观察效应的协程 (类) | |
| (C++20) |
std::coroutine_handle<std::noop_coroutine_promise>，旨在指代空操作协程 (类型别名) | |
平凡可等待对象 | ||
| (C++20) |
指示 await 表达式应永不挂起 (类) | |
| (C++20) |
指示 await 表达式应始终挂起 (类) | |
函数 | ||
| (C++20) |
比较两个 coroutine_handle 对象(函数) | |
空操作协程 | ||
| (C++20) |
创建一个协程句柄，该句柄在恢复或销毁时没有可观察的效应 (函数) | |
[编辑] 概要
#include <compare> namespace std { // coroutine traits template<class R, class... ArgTypes> struct coroutine_traits; // coroutine handle template<class Promise = void> struct coroutine_handle; // comparison operators constexpr bool operator==(coroutine_handle<> x, coroutine_handle<> y) noexcept; constexpr strong_ordering operator<=>(coroutine_handle<> x, coroutine_handle<> y) noexcept; // hash support template<class T> struct hash; template<class P> struct hash<coroutine_handle<P>>; // no-op coroutines struct noop_coroutine_promise; template<> struct coroutine_handle<noop_coroutine_promise>; using noop_coroutine_handle = coroutine_handle<noop_coroutine_promise>; noop_coroutine_handle noop_coroutine() noexcept; // trivial awaitables struct suspend_never; struct suspend_always; }
[编辑] 类模板 std::coroutine_handle
namespace std { template<> struct coroutine_handle<void> { // construct/reset constexpr coroutine_handle() noexcept; constexpr coroutine_handle(nullptr_t) noexcept; coroutine_handle& operator=(nullptr_t) noexcept; // export/import constexpr void* address() const noexcept; static constexpr coroutine_handle from_address(void* addr); // observers constexpr explicit operator bool() const noexcept; bool done() const; // resumption void operator()() const; void resume() const; void destroy() const; private: void* ptr; // exposition only }; template<class Promise> struct coroutine_handle { // construct/reset constexpr coroutine_handle() noexcept; constexpr coroutine_handle(nullptr_t) noexcept; static coroutine_handle from_promise(Promise&); coroutine_handle& operator=(nullptr_t) noexcept; // export/import constexpr void* address() const noexcept; static constexpr coroutine_handle from_address(void* addr); // conversion constexpr operator coroutine_handle<>() const noexcept; // observers constexpr explicit operator bool() const noexcept; bool done() const; // resumption void operator()() const; void resume() const; void destroy() const; // promise access Promise& promise() const; private: void* ptr; // exposition only }; }
[编辑] 类 std::noop_coroutine_promise
namespace std { struct noop_coroutine_promise {}; }
[编辑] 类 std::coroutine_handle<std::noop_coroutine_promise>
namespace std { template<> struct coroutine_handle<noop_coroutine_promise> { // conversion constexpr operator coroutine_handle<>() const noexcept; // observers constexpr explicit operator bool() const noexcept; constexpr bool done() const noexcept; // resumption constexpr void operator()() const noexcept; constexpr void resume() const noexcept; constexpr void destroy() const noexcept; // promise access noop_coroutine_promise& promise() const noexcept; // address constexpr void* address() const noexcept; private: coroutine_handle(/* unspecified */); void* ptr; // exposition only }; }
[编辑] 类 std::suspend_never
namespace std { struct suspend_never { constexpr bool await_ready() const noexcept { return true; } constexpr void await_suspend(coroutine_handle<>) const noexcept {} constexpr void await_resume() const noexcept {} }; }
[编辑] 类 std::suspend_always
namespace std { struct suspend_always { constexpr bool await_ready() const noexcept { return false; } constexpr void await_suspend(coroutine_handle<>) const noexcept {} constexpr void await_resume() const noexcept {} }; }
