Standard library header <coroutine>
From cppreference.com
This header is part of the coroutine support library.
Includes | |
(C++20) |
Three-way comparison operator support |
Classes | |
(C++20) |
trait type for discovering coroutine promise types (class template) |
(C++20) |
used to refer to a suspended or executing coroutine (class template) |
hash support for std::coroutine_handle (class template specialization) | |
No-op Coroutines | |
(C++20) |
used for coroutines with no observable effects (class) |
(C++20) |
std::coroutine_handle<std::noop_coroutine_promise>, intended to refer to a no-op coroutine (typedef) |
Trivial Awaitables | |
(C++20) |
indicates that an await-expression should never suspend (class) |
(C++20) |
indicates that an await-expression should always suspend (class) |
Functions | |
(C++20) |
compares two coroutine_handle objects (function) |
No-op Coroutines | |
(C++20) |
creates a coroutine handle that has no observable effects when resumed or destroyed (function) |
Synopsis
#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; }
Class template 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 }; }
Class std::noop_coroutine_promise
namespace std { struct noop_coroutine_promise {}; }
Class 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 }; }
Class 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 {} }; }
Class 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 {} }; }