## +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

1.jpg) ## I ntel Baremetal Senders  ## Sender Factories ## Functions that return senders • just • just_result_of • • just_stopped 1 auto sndr = async::just(42, 17); ## Sender Factories ## Functions that return senders • just • just_result_of • just_error • just_error_result_of • just_stopped 1 auto sndr = a 17; }; ## Sender Factories ## Functions that return senders • schedule 1 auto sndr = sched.schedule(); ## Sender Adapters ## Take one or more senders and returns a sender that is the composition • continue_on

I'm 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 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

connection. - CFC uses a credit 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 processors and is 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

sending values to a closed channel will panic, so it is dangerous to send values to a channel if the senders don't know whether or not the channel is closed. The criticisms look reasonable (in fact not) channel from the receiver side and don't close a channel if the channel has multiple concurrent senders. In other words, we should only close a channel in a sender goroutine if the sender is the only sender goroutine can close the channel safely. However, making such guarantees by a receiver or by one of many senders of a channel usually needs much effort, and often makes code complicated. On the contrary, it is

sending values to a closed channel will panic, so it is dangerous to send values to a channel if the senders don't know whether or not the channel is closed. The criticisms look reasonable (in fact not) channel from the receiver side and don't close a channel if the channel has multiple concurrent senders. In other words, we should only close a channel in a sender goroutine if the sender is the only sender goroutine can close the channel safely. However, making such guarantees by a receiver or by one of many senders of a channel usually needs much effort, and often makes code complicated. On the contrary, it is

sending values to a closed channel will panic, so it is dangerous to send values to a channel if the senders don't know whether or not the channel is closed. The criticisms look reasonable (in fact not) channel from the receiver side and don't close a channel if the channel has multiple concurrent senders. In other words, we should only close a channel in a sender goroutine if the sender is the only sender goroutine can close the channel safely. However, making such guarantees by a receiver or by one of many senders of a channel usually needs much effort, and often makes code complicated. On the contrary, it is

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 consumers on the queue but a particular 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) transaction to ensure ACID properties. ## Publish-Subscribe With publish-subscribe messaging many senders can send messages to an entity on the server, often called a topic (e.g. in the JMS world). There