C++ Actor Framework  0.18

A trivial example program.

#include <string>
#include <iostream>
#include "caf/actor_ostream.hpp"
#include "caf/actor_system.hpp"
#include "caf/caf_main.hpp"
#include "caf/event_based_actor.hpp"
using namespace caf;
behavior mirror(event_based_actor* self) {
// return the (initial) actor behavior
return {
// a handler for messages containing a single string
// that replies with a string
[=](const std::string& what) -> std::string {
// prints "Hello World!" via aout (thread-safe cout wrapper)
aout(self) << what << std::endl;
// reply "!dlroW olleH"
return std::string{what.rbegin(), what.rend()};
void hello_world(event_based_actor* self, const actor& buddy) {
// send "Hello World!" to our buddy ...
self->request(buddy, std::chrono::seconds(10), "Hello World!")
// ... wait up to 10s for a response ...
[=](const std::string& what) {
// ... and print it
aout(self) << what << std::endl;
void caf_main(actor_system& sys) {
// create a new actor that calls 'mirror()'
auto mirror_actor = sys.spawn(mirror);
// create another actor that calls 'hello_world(mirror_actor)';
sys.spawn(hello_world, mirror_actor);
// the system will wait until both actors are done before exiting the program
// creates a main function for us that calls our caf_main