...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Run the io_service's event processing loop to execute ready handlers.
std::size_t poll();
The poll() function runs handlers that are ready to run, without blocking, until the io_service has been stopped or there are no more ready handlers.
The number of handlers that were executed.
Thrown on failure.