ise> ## Awaitable & awaiter & co_await co_await is a unary operator(so in case the compiler can find the definition of operator function, it is valid) • awaitable - type supports co_await code. 1. Retrieve awaiter & awaitable 2. Awaiting the awaiter (suspend and resume happens here) Useful to know According to the definition, a type can be awaitable and awaiter at the same time It's string" or in general co_await on some un-awaitable expressions. Or prohibit co_await on certain types. Check out Promise::await_transform ## co_await is Awaitable is ... Awaiter is ... At the compile

inject_stop_request_thunk<...>(..._sa_task) () at /home/cppcon/c 5 : auto unifex::connect_awaitable(task, receiver auto&) () at /home/cppcon/cppcon24-async 6 : unifex::task async_main< _promise:await_transform(...) () at /home/cppcon/cppcon24-async-demo/lib 13: auto unifex::connect_awaitable(task, receiver auto&) () at /home/cppcon/cppcon24-async 14: main () at /home/cppcon/ ..sa_task) () at task.hpp:824 5 : auto unifex::connect_awaitable(task, receiver auto&)() at connect_awaitable.hpp:234 6 : unifex::task async_main<...>(span, auto&

unhandled_exception(); std::suspend_always final_suspend() noexcept; }; }; ## Awaitable struct Available { bool await_ready(); auto await_suspend(std::coroutine_handle); inner_function(); Async middle_function() { Async awaitable = inner_function(); auto r = co_await awaitable; co_return PartialResult::from_io_result(r); } inner_function(); Async middle_function() { Async awaitable = inner_function(); auto r = co_await awaitable; co_return PartialResult::from_io_result(r); }

use_awaitable); // read data auto buf = make_unique(len); co_await async_read(s, buffer(buf.get(), len), use_awaitable); // ...handle data buffer(&len, sizeof(len)), use_awaitable); // read data auto buf = make_unique(len); co_await async_read(s, buffer(buf.get(), len), use_awaitable); // ...handle data... ## [&s, &buf() -> asio::awaitable { co_await s.read_some(s, asio::buffer(buf), asio::use_awaitable); }, asio::detached); }

use tornado.gen.convert_yielded. – always return a Future object. Native coroutines return an awaitable object that is not a Future. In Tornado the two are mostly interchangeable. 16 Chapter 6. Documentation Coroutines do not raise exceptions in the normal way: any exception they raise will be trapped in the awaitable object until it is yielded. This means it is important to call coroutines in the right way, or you Application([ (r'/user/(.*)', ProfileHandler, dict(database=database)), ]) RequestHandler.prepare() → Awaitable[None] | None Called at the beginning of a request before get/post/etc. Override this method to perform

use tornado.gen.convert_yielded. - always return a Future object. Native coroutines return an awaitable object that is not a Future. In Tornado the two are mostly interchangeable. ## How it works This Coroutines do not raise exceptions in the normal way: any exception they raise will be trapped in the awaitable object until it is yielded. This means it is important to call coroutines in the right way, or you method with gen.coroutine to make it asynchronous. If this method returns an Awaitable execution will not proceed until the Awaitable is done. New in version 3.1: Asynchronous support. RequestHandler.on_finish()

use tornado.gen.convert_yielded. - always return a Future object. Native coroutines return an awaitable object that is not a Future. In Tornado the two are mostly interchangeable. ## How it works This Coroutines do not raise exceptions in the normal way: any exception they raise will be trapped in the awaitable object until it is yielded. This means it is important to call coroutines in the right way, or you method with gen.coroutine to make it asynchronous. If this method returns an Awaitable execution will not proceed until the Awaitable is done. New in version 3.1: Asynchronous support. RequestHandler.on_finish()

coroutines, use tornado.gen.convert_yielded. always return a Future object. Native coroutines return an awaitable object that is not a Future. In Tornado the two are mostly interchangeable. ## How it works This Coroutines do not raise exceptions in the normal way: any exception they raise will be trapped in the awaitable object until it is yielded. This means it is important to call coroutines in the right way, or you method with gen.coroutine to make it asynchronous. If this method returns an Awaitable execution will not proceed until the Awaitable is done. New in version 3.1: Asynchronous support. RequestHandler.on_finish()

use tornado.gen.convert_yielded. - always return a Future object. Native coroutines return an awaitable object that is not a Future. In Tornado the two are mostly interchangeable. ## How it works This Coroutines do not raise exceptions in the normal way: any exception they raise will be trapped in the awaitable object until it is yielded. This means it is important to call coroutines in the right way, or you method with gen.coroutine to make it asynchronous. If this method returns an Awaitable execution will not proceed until the Awaitable is done. New in version 3.1: Asynchronous support. RequestHandler.on_finish()

use tornado.gen.convert_yielded. - always return a Future object. Native coroutines return an awaitable object that is not a Future. In Tornado the two are mostly interchangeable. ## How it works This Coroutines do not raise exceptions in the normal way: any exception they raise will be trapped in the awaitable object until it is yielded. This means it is important to call coroutines in the right way, or you method with gen.coroutine to make it asynchronous. If this method returns an Awaitable execution will not proceed until the Awaitable is done. New in version 3.1: Asynchronous support. RequestHandler.on_finish()