Event-driven Server getSocket(ZMQ::SOCKET_REP); // Connect the socket $rep->bind("tcp://127.0.0.1:5555"); // Get the stream descriptor $fd = $rep->getsockopt(ZMQ::SOCKOPT_FD); // Define event callback function $fnc = function ($fd, $events, $arg) { static $msgs = 1; echo "CALLBACK FIRED" . PHP_EOL; if($arg[0]->getsockopt (ZMQ::SOCKOPT_EVENTS) & ZMQ::POLL_IN) { echo "Got incoming data" . PHP_EOL; var_dump ($arg[0]->recv()); $arg[0]->send("Got msg $msgs"); if($msgs++ >= 10) event_base_loopexit($arg[1]); } }; // set event flags event_set($event, $fd, EV_READ | EV_PERSIST, $fnc, array($rep, $base)); // set event base event_base_set($event, $base); // enable event event_add($event); // start event loop event_base_loop($base); ]]> ZeroMQ Client connect("tcp://127.0.0.1:5555"); // Assign socket 1 to the queue, send and receive var_dump($queue->send("hello there!")->recv()); ]]>