NAME

       zmq_connect - create outgoing connection from socket

SYNOPSIS

       int zmq_connect (void *socket, const char *endpoint);

DESCRIPTION

       The zmq_connect() function connects the socket to an endpoint and then accepts incoming connections on
       that endpoint.

       The endpoint is a string consisting of a transport:// followed by an address. The transport specifies the
       underlying protocol to use. The address specifies the transport-specific address to connect to.

       0MQ provides the the following transports:

       tcp
           unicast transport using TCP, see zmq_tcp(7)

       ipc
           local inter-process communication transport, see zmq_ipc(7)

       inproc
           local in-process (inter-thread) communication transport, see zmq_inproc(7)

       pgm, epgm
           reliable multicast transport using PGM, see zmq_pgm(7)

       vmci
           virtual machine communications interface (VMCI), see zmq_vmci(7)

       Every 0MQ socket type except ZMQ_PAIR supports one-to-many and many-to-one semantics. The precise
       semantics depend on the socket type and are defined in zmq_socket(3).

           Note

           for most transports and socket types the connection is not performed immediately but as needed by
           0MQ. Thus a successful call to zmq_connect() does not mean that the connection was or could actually
           be established. Because of this, for most transports and socket types the order in which a server
           socket is bound and a client socket is connected to it does not matter. The ZMQ_PAIR sockets are an
           exception, as they do not automatically reconnect to endpoints.

           Note

           following a zmq_connect(), for socket types except for ZMQ_ROUTER, the socket enters its normal ready
           state. By contrast, following a zmq_bind() alone, the socket enters a mute state in which the socket
           blocks or drops messages according to the socket type, as defined in zmq_socket(3). A ZMQ_ROUTER
           socket enters its normal ready state for a specific peer only when handshaking is complete for that
           peer, which may take an arbitrary time.

           Note

           for some socket types, multiple connections to the same endpoint don’t really make sense (see
           https://github.com/zeromq/libzmq/issues/788). For those socket types, any attempt to connect to an
           already connected endpoint is silently ignored (i.e., returns zero). This behavior applies to
           ZMQ_DEALER, ZMQ_SUB, ZMQ_PUB, and ZMQ_REQ socket types.

RETURN VALUE

       The zmq_connect() function returns zero if successful. Otherwise it returns -1 and sets errno to one of
       the values defined below.

ERRORS

       EINVAL
           The endpoint supplied is invalid.

       EPROTONOSUPPORT
           The requested transport protocol is not supported.

       ENOCOMPATPROTO
           The requested transport protocol is not compatible with the socket type.

       ETERM
           The 0MQ context associated with the specified socket was terminated.

       ENOTSOCK
           The provided socket was invalid.

       EMTHREAD
           No I/O thread is available to accomplish the task.

EXAMPLE

       Connecting a subscriber socket to an in-process and a TCP transport.

           /* Create a ZMQ_SUB socket */
           void *socket = zmq_socket (context, ZMQ_SUB);
           assert (socket);
           /* Connect it to an in-process transport with the address 'my_publisher' */
           int rc = zmq_connect (socket, "inproc://my_publisher");
           assert (rc == 0);
           /* Connect it to the host server001, port 5555 using a TCP transport */
           rc = zmq_connect (socket, "tcp://server001:5555");
           assert (rc == 0);

SEE ALSO

       zmq_bind(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 4.3.2                                          04/21/2020                                     ZMQ_CONNECT(3)