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.

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  • 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 mupltiple consumers) messaging, aka pub-sub
  • cross-platform (windows, macosx, linux)
  • inspired by [The Reactive Manifesto](reactive) and sobjectizer




Please read tutorial, design principles and manual here


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 L√≥pez 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.