1ZMQ_CONNECT(3)                    0MQ Manual                    ZMQ_CONNECT(3)
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NAME

6       zmq_connect - create outgoing connection from socket
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SYNOPSIS

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

12       The zmq_connect() function connects the socket to an endpoint and then
13       accepts incoming connections on that endpoint.
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15       The endpoint is a string consisting of a transport:// followed by an
16       address. The transport specifies the underlying protocol to use. The
17       address specifies the transport-specific address to connect to.
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19       0MQ provides the the following transports:
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21       tcp
22           unicast transport using TCP, see zmq_tcp(7)
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24       ipc
25           local inter-process communication transport, see zmq_ipc(7)
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27       inproc
28           local in-process (inter-thread) communication transport, see
29           zmq_inproc(7)
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31       pgm, epgm
32           reliable multicast transport using PGM, see zmq_pgm(7)
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34       vmci
35           virtual machine communications interface (VMCI), see zmq_vmci(7)
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37       udp
38           unreliable unicast and multicast using UDP, see zmq_udp(7)
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40       Every 0MQ socket type except ZMQ_PAIR and ZMQ_CHANNEL supports
41       one-to-many and many-to-one semantics. The precise semantics depend on
42       the socket type and are defined in zmq_socket(3).
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44           Note
45           for most transports and socket types the connection is not
46           performed immediately but as needed by 0MQ. Thus a successful call
47           to zmq_connect() does not mean that the connection was or could
48           actually be established. Because of this, for most transports and
49           socket types the order in which a server socket is bound and a
50           client socket is connected to it does not matter. The ZMQ_PAIR and
51           ZMQ_CHANNEL sockets are an exception, as they do not automatically
52           reconnect to endpoints.
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54           Note
55           following a zmq_connect(), for socket types except for ZMQ_ROUTER,
56           the socket enters its normal ready state. By contrast, following a
57           zmq_bind() alone, the socket enters a mute state in which the
58           socket blocks or drops messages according to the socket type, as
59           defined in zmq_socket(3). A ZMQ_ROUTER socket enters its normal
60           ready state for a specific peer only when handshaking is complete
61           for that peer, which may take an arbitrary time.
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63           Note
64           for some socket types, multiple connections to the same endpoint
65           don’t really make sense (see
66           https://github.com/zeromq/libzmq/issues/788). For those socket
67           types, any attempt to connect to an already connected endpoint is
68           silently ignored (i.e., returns zero). This behavior applies to
69           ZMQ_DEALER, ZMQ_SUB, ZMQ_PUB, and ZMQ_REQ socket types.
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RETURN VALUE

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

76       EINVAL
77           The endpoint supplied is invalid.
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79       EPROTONOSUPPORT
80           The requested transport protocol is not supported.
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82       ENOCOMPATPROTO
83           The requested transport protocol is not compatible with the socket
84           type.
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86       ETERM
87           The 0MQ context associated with the specified socket was
88           terminated.
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90       ENOTSOCK
91           The provided socket was invalid.
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93       EMTHREAD
94           No I/O thread is available to accomplish the task.
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EXAMPLE

97       Connecting a subscriber socket to an in-process and a TCP transport.
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99           /* Create a ZMQ_SUB socket */
100           void *socket = zmq_socket (context, ZMQ_SUB);
101           assert (socket);
102           /* Connect it to an in-process transport with the address 'my_publisher' */
103           int rc = zmq_connect (socket, "inproc://my_publisher");
104           assert (rc == 0);
105           /* Connect it to the host server001, port 5555 using a TCP transport */
106           rc = zmq_connect (socket, "tcp://server001:5555");
107           assert (rc == 0);
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SEE ALSO

111       zmq_bind(3) zmq_socket(3) zmq(7)
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AUTHORS

114       This page was written by the 0MQ community. To make a change please
115       read the 0MQ Contribution Policy at
116       http://www.zeromq.org/docs:contributing.
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1200MQ 4.3.4                         07/23/2022                    ZMQ_CONNECT(3)
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