## +24 ## How Meta Made Debugging Async Code Easier with Coroutines and Senders IAN PETERSEN & JESSICA WONG ## Stack Traces for Async Code are Unhelpful IO Thread: ![Image](/uploads/documents

Some simple examples, intro to senders 3. The lifecycle of an async operation 4. Under the hood of a concurrent operation 5. Implementing a simple algorithm 6. Senders and coroutines ## Part 2: 1 ex::then([] { return compute_intensive(2); }) ex::then([] { return compute_intensive(0); }); ## SENDERS ARE EXPRESSION TEMPLATES when all then then then schedule schedule schedule ex::sender auto ex::then([] { return compute_intensive(1); }); ex::then([] { return compute_intensive(2); }); ## SENDERS ARE EXPRESSION TEMPLATES when all then then then schedule schedule schedule ## ex::sender

achieve best results, there should be some amount of uniformity between coroutine types ☑ C++26 senders/receivers are a first step in this direction, but a lot is still in development there ☑ C++ Coroutines Server Ian Petersen, Jessica Wong - How Meta Made Debugging Async Code Easier with Coroutines and Senders ■ Dmitry Prokoptsev - Coroutines and Structured Concurrency in Practice ☑ Michael Caisse - Sender

system to signal the availability of buffer space from receivers to senders. - Senders maintain a credit balance for all their receivers and receivers regularly send notifications upstream containing their implemented in Apache Flink. - Each task informs its senders of its buffer availability via credit messages. - This way, senders always know whether receivers have the required capacity to handle data messages

<=> tmp := Book{100}; p := &tmp p.Pages = 200 } ## I n Field Selectors, Dereferences of Receivers Can Be Implicit In the following example, for simplicity, (*bookN).pages could be written as bookN names in Go. The receiver of type $ *T $ is called pointer receiver, non-pointer receivers are called value receivers. Personally, I don't recommend to view the terminology pointer as an opposite *Book) SetPages(pages int) { (*Book).SetPages(b, pages) } ## I mplicit Methods With Pointer Receivers For each method declared for value receiver type T, a corresponding method with the same name will

tmp := Book{100}; p := &tmp 10| p.Pages = 200 11| } ## I n Field Selectors, Dereferences of Receivers Can Be Implicit In the following example, for simplicity, (*bookN).pages could be written as bookN names in Go. The receiver of type $ *T $ is called pointer receiver, non-pointer receivers are called value receivers. Personally, I don't recommend to view the terminology pointer as an opposite *Book) SetPages(pages int) { 6| (*Book).SetPages(b, pages) 7| } ## I mplicit Methods With Pointer Receivers For each method declared for value receiver type T, a corresponding method with the same name will

talking to the wrong crowd. Hello C++ grammar. ## ASYNCHRONOUS EXECUTION Let's talk about senders and receivers for a minute. I'm pretty sure the authors of P2300 made a conscious decision to excise sender upon_[error|done] (sender, fn) → sender let_[value|...] (sender, fn) → sender when all(senders...) → sender on(scheduler, sender) → sender into variant(sender) → sender bulk(sender, size, fn) result of input sender to function, which returns new sender. ... completes when all the input senders complete. ... starts the input sender in the context of the input scheduler. ... packages all possible

:= Book{100}; p := &tmp 10| | p.Pages = 200 11| | } # In Field Selectors, Dereferences of Receivers Can Be Implicit In the following example, for simplicity, (*bookN).pages could be written as bookN names in Go. The receiver of type $ *T $ is called pointer receiver, non-pointer receivers are called value receivers. Personally, I don't recommend to view the terminology pointer as an opposite *Book) SetPages(pages int) { 6| (*Book).SetPages(b, pages) 7| } ## I mplicit Methods With Pointer Receivers For each method declared for value receiver type T, a corresponding method with the same name will

249 40.5. Dual Mirror (Disaster Recovery) ..... 251 40.6. Example ..... 252 40.7. Senders and Receivers ..... 252 40.8. Peers ..... 254 40.9. Address Consideration ..... 255 40.10. Federation much higher performance applications. Messaging systems decouple the senders of messages from the consumers of messages. The senders and consumers of messages are completely independent and know nothing message will only ever be consumed by a maximum of one of them. Senders (also known as producers) to the queue are completely decoupled from receivers (also known as consumers) of the queue - they do not know

249 40.5. Dual Mirror (Disaster Recovery) ..... 251 40.6. Example ..... 252 40.7. Senders and Receivers ..... 252 40.8. Peers ..... 254 40.9. Address Consideration ..... 255 40.10. Federation much higher performance applications. Messaging systems decouple the senders of messages from the consumers of messages. The senders and consumers of messages are completely independent and know nothing message will only ever be consumed by a maximum of one of them. Senders (also known as producers) to the queue are completely decoupled from receivers (also known as consumers) of the queue - they do not know