zmq_connect(3)

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.

ØMQ 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) +
+

Every ØMQ 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 ØMQ. 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 first exception is when using the inproc:// transport: you must +call zmq_bind() before calling zmq_connect(). The second exception are +ZMQ_PAIR sockets, which 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.

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 ØMQ 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);

AUTHORS

This page was written by the ØMQ community. To make a change please +read the ØMQ Contribution Policy at http://www.zeromq.org/docs:contributing.

+zmq_connect(3) Manual Page +

NAME