rotor is event loop friendly C++ actor micro framework.

That means, that rotor is probably useless without event loop, e.g. boost-asio or wx-widgets event loop; as a framework rotor imposes some usage patters of actor-model, however their amount a bare minimum, hence it is micro framework.

As actor model and event loops are asynchronous by their nature, the underlying intuition is to uplift the low level events of an event loop into high-level messages between actors, making high-level messages abstracted from the event loop; hence rotor should provide message passing facilities between actors independently from the used event loop(s).

rotor can be used in the applications, where different loop engines are used together and it is desirable to write some loop-agnostic logic still having message passing interface. The library can be used as lightweight loop abstraction with actor-like flavor.

Programming language: C++
License: MIT License
Latest version: v0.12

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rotor is event loop friendly C++ actor micro framework, github gitee

https://t.me/cpp_rotor CircleCI appveyor codecov Codacy Badge license


  • minimalistic loop agnostic core
  • erlang-like hierarchical supervisors, see
  • various event loops supported (wx, boost-asio, ev) or planned (uv, gtk, etc.)
  • asynchornous message passing interface
  • request-response messaging with cancellation capabilities, see
  • MPMC (multiple producers multiple consumers) messaging, aka pub-sub
  • cross-platform (windows, macosx, linux)
  • inspired by [The Reactive Manifesto](reactive) and sobjectizer


inter-thread messaging (1) cross-thread messaging (2)
~23.5M messages/second ~ 2.5M messages/second

Setup: Intel Core i7-8550U, Void Linux 5.13.

(1) Backend-independent; Can be measured with examples/boost-asio/ping-pong-single-simple, examples/ev/ping-pong-ev.

(2) Does not apply to wx-backend; can be measured with examples/thread/ping-pong-thread, examples/boost-asio/ping-pong-2-theads, examples/ev/ping-pong-ev-2-threads.




Please read tutorial, design principles and manual here


0.19 (31-Dec-2021)

  • [improvement] performance improvement in inter-thread (+20%) and cross-thread messaging
  • [bugfix] supervisor does not shut self down in rare conditions, when it fails to initialize self
  • [bugfix] link_server plugin should ignore unlink_notifications
  • [bugfix] avoid cycle (i.e. memleak) in rare cases when supervisor is shutdown, but an external message arrives for processing

0.18 (03-Dec-2021)

  • [improvement] add static_assert for noexcept check of a hanler signature
  • [improvement] add gitee mirror
  • [bugfix] fix potential use-after-free in ev backend

0.17 (23-Oct-2021)

  • [bugfix] fix installation issues with cmake (thanks to @melpon)
  • [bugfix] fix missing header (thanks to @melpon)
  • [ci] drop travis-ci in the sake of circle-ci

0.16 (22-Aug-2021)

  • [improvement] significant message throughtput increase for std::thread, boost-asio and ev backends (upto 5x times)
  • [improvement] extended_error can now access to root reason
  • [improvement] delivery plugin in debug mode dumps discovery requests and responses
  • [improvement/breaking] more details on fatal error (system_context)
  • [example] examples/thread/ping-pong-thread.cpp (new)
  • [example] examples/ev/ping-pong-ev-2-threads (new)

0.15 (02-Apr-2021)

  • [bugfix] lifetime_plugin_t do not unsubscribe from foreign to me subscriptions
  • [bugfix] foreigners_support_plugin_t more safely deliver a message for a foreign subscriber (actor)

0.14 (20-Feb-2021)

  • the dedicated article with highlights: en and ru
    • [improvement] actor identity has been introduced. It can be configured or generated via address_maker plugin
    • [improvement] actor::do_shutdown() - optionally takes shutdown reason
    • [improvement/breaking] instead of using std::error_code the extended_error class is used. It wraps std::error_code, provides string context and pointer to the next extended_error cause. This greatly simplfies error tracking of errors. Every response now contains ee field instead of ec.
    • [improvement] actor has shutdown reason (in form of extended_error pointer)
    • [improvement] delivery plugin in debug mode it dumps shutdown reason in shutdown trigger messages
    • [improvement] actor identity has on_unlink method to get it know, when it has been unlinked from server actor
    • [improvement] add resources plugin for supervisor
    • [breaking] all responses now have extended_error pointer instread of std::error_code
    • [breaking] shutdown_request_t and shutdown_trigger_t messages how have shutdown reason (in form of extended_error pointer)
    • [bugfix] link_client_plugin_t do not invoke custom callback, before erasing request in case of failure
    • [bugfix] child_manager_plugin_t reactivate self if a child was created from other plugin.
    • [bugfix] registy actor incorrectly resolves postponed requests to wrong addresses

0.13 (26-Dec-2020)

  • [improvement] delivery plugin in debug mode dumps discarded messages
  • [breaking] state_response_t has been removed
  • [bugfix] allow to acquire & release resources in via resources_plugin_t, during other plugin configuration
  • [bugfix] foreigners_support_plugin_t did not deactivated self properly, caused assertion fail on supervisor shutdown, when there was foreign subscriptions
  • [bugfix] link_client_plugin_t did not notified linked server-actors, if its actor is going to shutdown; now server-actors are requested to unlink
  • [bugfix] starter_plugin_t sometimes crashed when subscription confirmation message arrives when actor is in non-initializing phase (i.e. shutting down)
  • [bugfix] root supervisor is not shutdown properly when it is linked as "server"

0.12 (08-Dec-2020)

  • [improvement] added std::thread backend (supervisor)
  • [bugfix] active timers, if any, are cancelled upon actor shutdown finish
  • [bugfix] supervisor shutdown message is lost in rare cases right after child actor start
  • [example] examples/thread/sha512.cpp (new)
  • [documentation] updated Event loops & platforms
  • [documentation] updated Patterns with Blocking I/O multiplexing
  • [deprecated] state_response_t, state_request_t will be removed in v0.13

0.11 (20-Nov-2020)

  • [improvement] when supervisor shuts self down due to child init failure, the supervisor init error code is "failure escalation"
  • [documentation] updated Advanced examples,
  • [bugfix] when actor shuts self down all its timers are properly cancelled
  • [bugfix] in rare case supervisor starts, event if child failed to init
  • [bugfix] asio: more correct timers cancellation implementation
  • [bugfix] ev: more correct shutdown (avoid memory leaks in rare cases)

0.10 (09-Nov-2020)

  • [improvement/breaking] Generic timers interface
  • [improvement] Request cancellation support
  • [improvement] added make_response methods when message should be created, but send later delayed
  • [improvement] more debug information in message delivery plugin
  • [documentation] Integration with event loops
  • [documentation] Requests cancellation and timers are demonstrated in the [Advanced Examples](docs/Examples.md) section
  • [example] examples/boost-asio/ping-pong-timer.cpp (new)
  • [example] examples/boost-asio/beast-scrapper.cpp (updated)
  • [bugfix] avoid double configuration of a plugin in certain cases when interacting with resources plugin
  • [bugfix] more correct cmake installation (thanks to Jorge López Tello, @LtdJorge)

0.09 (03-Oct-2020)

  • the dedicated article with highlights: en and ru
  • [improvement] rewritten whole documentation
  • [improvement/breaking] plugin system where introduced for actors instead of behaviors
  • [improvement] actor_config_t was introduced, which now holds pointer to supervisor, init and shutdown timeouts
  • [improvement] builder pattern was introduced to simplify actors construction
  • [breaking] supervisor_config_t was changed (inherited from actor_config_t)
  • [breaking] actor_base_t and supervisor_t constructors has changed - now appropriate config is taken as single parameter. All descendant classes should be changed
  • [breaking] if a custom config type is used for actors/supervisors, they should define config_t inside the class, and templated config_builder_t.
  • [breaking] supervisor in actor is now accessibe via pointer instead of refence
  • [bugfix] supervisor_ev_t not always correctly released EV-resources, which lead to leak
  • [bugfix] actor_base_t can be shutted down properly even if it did not started yet

0.08 (12-Apr-2020)

  • [bugfix] message's arguments are more correctly forwarded
  • [bugfix] actor's arguments are more correctly forwarded in actor's creation inrotor::supervisor_t and rotor::asio::supervisor_asio_t
  • [bugfix] rotor::asio::forwarder_t now more correctly dispatches boost::asio events to actor methods; e.g. it works correctly now with async_accept method of socket_acceptor

0.07 (02-Apr-2020)

  • [improvement] more modern cmake usage

0.06 (09-Nov-2019)

  • [improvement] registy actor was added to allow via name/address runtime matching do services discovery
  • [improvement, breaking] minor changes in supervisor behavior: now it is considered initialied when all its children confirmed initialization
  • [improvement] supervisor_policy_t was introduced to control supervisor behavior on a child-actor startup failure
  • [example] examples/ev/pong-registry.cpp how to use registry
  • [doc] patterns/Registry was added

0.05 (22-Sep-2019)

  • [improvement] response can be inherited from rotor::arc_base, to allow forwarding requests without copying it (i.e. just intrusive pointer is created)
  • [example] examples/boost-asio/beast-scrapper.cpp has been added; it demonstrates an app with pool of actor workers with request-response forwarding

0.04 (14-Sep-2019)

  • [improvement] the request-response approach is integrated to support basic reliable messaging: response notification failure will be delivered, if the expected response will not arrive in-time
  • [improvement] lambda subscribiers are supported
  • [improvement] actor behavior has been introduced to offload actor's interface
  • [breaking] supervisor is constructed with help of supervisor_config_t, which contains shutdown timeout value
  • [breaking] supervisor does not spawns timeout timer for overall shutdown procedure, instead per-child timers are spawned. The root supervisor the same way monitors child-supervisor shut down
  • [breaking] supervisor create_actor method now takes child max init time value. If it does not confirm, the child actor will be asked for shut down.
  • [breaking] shutdown request sent to an child actor now timeout-tracked by supervisor. The message type has changed to message::shutdown_request_t
  • [breaking] init request sent to an child actor now timeout-tracked by supervisor. The message type has changed to message::init_request_t
  • [breaking] actor's state request message type now message::state_request_t, which follows the generic request/response pattern. The response type is now message::state_response_t.
  • [breaking] {asio, ev, ws} supervisor configs are renamed to have corresponding suffix.

0.03 (25-Aug-2019)

  • [improvement] locality notion was introduced, which led to possibilty to build superving trees, see blog-cpp-supervisors
  • [breaking] the outbound field in rotor::supervisor_t was renamed just to queue
  • [breaking] rotor::address_t now contains const void* locality
  • [breaking] rotor::asio::supervisor_config_t now contains std::shared_ptr to strand, instead of creating private strand for each supervisor
  • [bugfix] redundant do_start() method in rotor::supervisor_t was removed, since supervisor now is able to start self after compliting initialization.
  • [bugfix] rotor::supervisor_t sends initialize_actor_t to self to advance own state to INITIALIZED via common actor mechanism, instead of changeing state directly on early initialization phase (do_initialize)
  • [bugfix] rotor::asio::forwarder_t now more correctly dispatches boost::asio events to actor methods
  • [bugfix] rotor::ev::supervisor_ev_t properly handles refcounter

0.02 (04-Aug-2019)

  • Added libev support

0.01 (24-Jul-2019)

Initial version

*Note that all licence references and agreements mentioned in the rotor README section above are relevant to that project's source code only.