Question

io_service::poll_one Run the io_service object’s event processing loop
to execute one ready handler.

vs

io_service::run_one Run the io_service object’s event processing loop
to execute at most one handler.

From that explanation it would seem poll_one could execute more than one handler? Does run_one or poll_one use any thread that’s called run() or only the thread that calls poll_one/run_one?

The documentation for ASIO is very sparse.

Answer 1

poll_one will return immediately (non-blocking) in case there is no event to process.

run_one will block the calling thread until one event is ready to process.

You could also check some documentation here