ZMQ_PROXY_STEERABLE(3) 0MQ Manual ZMQ_PROXY_STEERABLE(3) NAME zmq_proxy_steerable - built-in 0MQ proxy with control flow SYNOPSIS int zmq_proxy_steerable (const void *frontend, const void *backend, const void *capture, const void *control); DESCRIPTION The zmq_proxy_steerable() function is a variant of the zmq_proxy() func- tion. It accepts a fourth control socket. When the control socket is NULL the two functions operate identically. When a control socket of type REP is provided to the proxy function the ap- plication may send commands to the proxy. The following commands are sup- ported. PAUSE The proxy will cease transferring messages between its endpoints. RESUME The proxy will resume transferring messages between its endpoints. TERMINATE The proxy function will exit with a return value of 0. STATISTICS The proxy behavior will remain unchanged and reply with a set of simple summary values of the messages that have been sent through the proxy as described next. There are eight statistics values, each of size uint64_t in the multi-part message reply to the STATISTICS command. These are: * number of messages received by the frontend socket * number of bytes received by the frontend socket * number of messages sent by the frontend socket * number of bytes sent by the frontend socket * number of messages received by the backend socket * number of bytes received by the backend socket * number of messages sent by the backend socket * number of bytes sent by the backend socket RETURN VALUE The zmq_proxy_steerable() function returns 0 if TERMINATE is received on its control socket. Otherwise, it returns -1 and errno set to ETERM or EINTR (the 0MQ context associated with either of the specified sockets was terminated) or EFAULT (the provided frontend or backend was invalid). EXAMPLE Create a function to run the proxy. // Create the frontend and backend sockets to be proxied void *frontend = zmq_socket (context, ZMQ_ROUTER); void *backend = zmq_socket (context, ZMQ_DEALER); // Create the proxy control socket void *control = zmq_socket (context, ZMQ_REP); // Bind the sockets. zmq_bind (frontend, "tcp://*:5555"); zmq_bind (backend, "tcp://*:5556"); zmq_bind (control, "tcp://*:5557"); zmq_proxy_steerable(frontend, backend, NULL, control); Code in another thread/process to steer the proxy.. void *control = zmq_socket (context, ZMQ_REQ); zmq_connect (control, "tcp://*:5557"); zmq_msg_t msg; zmq_send (control, "PAUSE", 5, 0); zmq_msg_recv (&msg, control, 0)); zmq_send (control, "RESUME", 6, 0); zmq_msg_recv (&msg, control, 0)); zmq_send (control, "STATISTICS", 10, 0); while (1) { zmq_msg_recv (&msg, control, 0)); printf(" %lu", *(uint64_t *)zmq_msg_data (&msg)); if (!zmq_msg_get (&msg, ZMQ_MORE)) break; } printf("\n"); zmq_send (control, "TERMINATE", 9, 0); zmq_msg_recv (&msg, control, 0)); zmq_close(frontend); zmq_close(backend); zmq_close(control); SEE ALSO zmq_proxy(3) zmq_bind(3) zmq_connect(3) zmq_socket(3) zmq(7) AUTHORS This page was written by the 0MQ community. To make a change please read the 0MQ Contribution Policy at http://www.zeromq.org/docs:contributing. 0MQ 4.3.5 10/09/2023 ZMQ_PROXY_STEERABLE(3)
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | EXAMPLE | SEE ALSO | AUTHORS
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