1ZMQ_CONNECT(3) 0MQ Manual ZMQ_CONNECT(3)
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6 zmq_connect - create outgoing connection from socket
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9 int zmq_connect (void *socket, const char *endpoint);
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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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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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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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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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111 zmq_bind(3) zmq_socket(3) zmq(7)
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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 01/30/2021 ZMQ_CONNECT(3)