io_service

This module provides an abstraction over Boost.ASIO, combining multiple asio::io_contexts into a single pool. hpx::util::io_service_pool provides a simple pool of asio::io_contexts with an API similar to asio::io_context. hpx::threads::detail::io_service_thread_pool wraps hpx::util::io_service_pool into an interface derived from hpx::threads::detail::thread_pool_base.

The module also provides sender-based timers. The :hpx:function:`hpx::io::experimental::schedule_timer_after` and :hpx:function:`hpx::io::experimental::schedule_timer_at` functions create senders that complete on an asio::io_context. Timer expiry produces set_value, cancellation through the receiver’s stop token produces set_stopped, and other timer errors produce set_error. The I/O context must be run until the operation completes.

Connecting a timer sender allocates shared operation state and an Asio timer. Callback storage may allocate as well. Applications creating timers in a hot loop should account for these allocations.

The following example creates a sender that completes after one second:

asio::io_context context;
auto sender = hpx::io::experimental::schedule_timer_after(
    context, std::chrono::seconds(1));

The sender can be composed with the other sender algorithms in HPX. Starting the sender does not itself run the I/O context.

See the API reference of this module for more details.