I use concurrency::task from ppltasks.h heavily in my codebase.
I would like to find a awaitable queue, where I can do "co_await my_queue.pop()". Has anyone implemented one?
Details: I have one producer thread that pushes elements to a queue, and another receiver thread would be waiting and waking up when elements arrive in the queue. This receiving thread might wait/wake up to handle other tasks in the meantime (using pplpp::when_any).
I don't want a queue with an interface where i have to poll a try_pop method as that is slow, and I don't want a blocking_pop method as that means I can't handle other ready tasks in the meantime.
This is basically your standard thread-safe queue implementation, but instead of a condition_variable, you will have to use futures to coordinate the different threads. You can then co_await on the future returned by pop to become ready.
The queue's implementation will need to keep a list of the promises that correspond to the outstanding pop calls. In case that the queue is still full when poping, you can return a ready future immediately. You can use plain old std::mutex to synchronize concurrent access to the underlying data structures.
I don't know of any implementation that already does this, but it shouldn't be too hard to pull off. Note though that managing all the futures will introduce some additional overhead, so your queue will probably be slightly less efficient than the classic condition_variable-based approach.