More notes/examples. Let me know if anything needs to be refined. In particular, are there other examples that would be useful, off the top of your head? --------------Services on Windows----------------- This is a complete (?) list of creatable on Windows NT 4.0 and above. **Services are created at run-time when a user-level object (e.g. a stream_socket) that needs them is created. **Services in this list with the same name will be re-used if they already exist. So, for example, if user creates a socket_acceptor then a stream_socket, the socket_acceptor will add the win_iocp_socket_service and the select_reactor<true> services, and then the stream_socket will find and re-use them. **The first item in each hierarchy is the user-level object whose instantiation creates the hierarchy. The reset of the items are services. demuxer demuxer_service win_iocp_demuxer_service stream_socket stream_socket_service win_iocp_socket_service select_reactor<true> datagram_socket datagram_socket_service win_iocp_socket_service select_reactor<true> acceptor_socket socket_acceptor_service win_iocp_socket_service select_reactor<true> deadline_timer deadline_timer_service reactive_deadline_timer_service select_reactor<true> locking_dispatcher locking_dispatcher_service [with one set of template parameters] locking_dispatcher_service [with another set of template parameters] (??) host_resolver host_resolver_service [with one set of template parameters] host_resolver_service [with another set of template parameters] (??) ssl::context context_service openssl_context_service ssl::stream stream_service openssl_stream_service --------------Platform differences---------------- Platform: Uses: linux 2.5.45 and above epoll Mac kqueue Windows NT 4.0 and above IoCompletionPort Everything else select In general specialized services look like this: Layer Class 0 user-level object 1 asio-level service 2 general-concept-implementation service 3 platform-implementation service In general specialized services look like this: Layer Example class 0 stream_socket 1 stream_socket_service 2 reactive_socket_service 3 epoll_reactor **For the demuxer_service and the socket services, WinNT 4.0 doesn't use the general-concept-implementation service but intstead has it's own "win_iocp-conecpt-implementation" classes. **All three socket services share the same conecept-implementation and platform-implementation-services. **Not all services have platform-specific implementations. locking_dispatcher, host_resolver and the ssl services context and stream are the same on all platforms. Comparison of specialized servives on Windows and Linux: SHARED NT LINUX 0 demuxer 1 demuxer_service 2 win_iocp_demuxer_service task_demuxer_service 3 [none] epoll_reactor<false> 0 stream_socket 1 stream_socket_service 2 win_iocp_socket_service reactive_socket_service 3 select_reactor<true> epoll_reactor<false> 0 datagram_socket 1 datagram_socket_service 2 win_iocp_socket_service reactive_socket_service 3 select_reactor<true> epoll_reactor<false> 0 acceptor_socket 1 socket_acceptor_service 2 win_iocp_socket_service reactive_socket_service 3 select_reactor<true> epoll_reactor<false> 0 deadline_timer 1 deadline_timer_service 2 reactive_deadline_timer_service 3 select_reactor<true> epoll_reactor<false> --------------------------Example------------------ Example of a Windows program using: *asynchronous timer callbacks, *asynchronous socket i/o, *tcp and udp *serving, via stream_socketasync_accept *one demuxer shared between timer and socket code. *no additional threads beyond main() and threads created by library. In this example, the demuxer is created first (it has to be), then a stream_socket is created, then an async_timer is created, finally demuxer::run is called. 1) demuxer::demuxer() creates: demuxer_service creates: win_iocp_demuxer_service The demuxer now has 2 services: demuxer_service win_iocp_demuxer_service No additional threads are running. The win_iocp_demuxer_service has allocated a Windows IoCompletionPort. 2) stream_socket::stream_socket(demuxer) creates: stream_socket_service creates: win_iocp_socket_service creates: select_reactor<true> (a service) The demuxer now has 5 services: demuxer_service win_iocp_demuxer_service stream_socket_service win_iocp_socket_service select_reactor<true> The select_reactor service has started a thread. The behavior of this thread depends on whether any async winsock calls are made If none are made the thread will call Sleep(till next timer expires); otherwise it will call select(with timeout when next timer expires). When this thread has nothing to do it will call select and wait to be interrupted. 3) datagram_socket::datagram_socket(demuxer) creates: datagram_socket_servivice finds already existing: win_iocp_socket_service The demuxer now has 6 services: demuxer_service win_iocp_demuxer_service stream_socket_service win_iocp_socket_service select_reactor<true> datagram_socket_service 4) acceptor_socket::acceptor_socket(demuxer) creates: socket_acceptor_service finds already existing: win_iocp_socket_service The demuxer now has 7 services: demuxer_service win_iocp_demuxer_service stream_socket_service win_iocp_socket_service select_reactor<true> datagram_socket_service socket_acceptor_service 5) deadline_timer::deadline_timer(demuxer) creates: deadline_timer_service creates: reactive_deadline_timer_service finds already existing: select_reactor<true> The demuxer now has 8 services: demuxer_service win_iocp_demuxer_service stream_socket_service win_iocp_socket_service select_reactor<true> deadline_timer_service reactive_deadline_timer_service No additional threads are running. However, in order to use asynchronous callbacks, demuxer::run must be called in some thread. 6) demuxer::run() is called in WinMain. There are now two threads running: select_reactor thread executes select_reactor which loops on Sleep(till next timer expires) main thread executes demuxer::run which loops on GetQueuedCompletionStatus and executes completion handlers.