From 8e61b98c5e2943b149c825310b24e714a6127072 Mon Sep 17 00:00:00 2001 From: Martin Lucina Date: Mon, 23 Jan 2012 08:53:41 +0100 Subject: Imported Upstream version 2.1.4 --- doc/zmq_device.html | 736 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 736 insertions(+) create mode 100644 doc/zmq_device.html (limited to 'doc/zmq_device.html') diff --git a/doc/zmq_device.html b/doc/zmq_device.html new file mode 100644 index 0000000..21a2fbc --- /dev/null +++ b/doc/zmq_device.html @@ -0,0 +1,736 @@ + + + + + +zmq_device(3) + + + + + +
+

SYNOPSIS

+
+

int zmq_device (int device, const void *frontend, const void *backend);

+
+

DESCRIPTION

+
+

The zmq_device() function starts a built-in ØMQ device. The device argument +is one of:

+
+
+ZMQ_QUEUE +
+
+

+ starts a queue device +

+
+
+ZMQ_FORWARDER +
+
+

+ starts a forwarder device +

+
+
+ZMQ_STREAMER +
+
+

+ starts a streamer device +

+
+
+

The device connects a frontend socket to a backend socket. Conceptually, data +flows from frontend to backend. Depending on the socket types, replies may flow +in the opposite direction.

+

Before calling zmq_device() you must set any socket options, and connect or +bind both frontend and backend sockets. The two conventional device models are:

+
+
+proxy +
+
+

+ bind frontend socket to an endpoint, and connect backend socket to + downstream components. A proxy device model does not require changes to + the downstream topology but that topology is static (any changes require + reconfiguring the device). +

+
+
+broker +
+
+

+ bind frontend socket to one endpoint and bind backend socket to a second + endpoint. Downstream components must now connect into the device. A broker + device model allows a dynamic downstream topology (components can come and + go at any time). +

+
+
+

zmq_device() runs in the current thread and returns only if/when the current +context is closed.

+
+

QUEUE DEVICE

+
+

ZMQ_QUEUE creates a shared queue that collects requests from a set of clients, +and distributes these fairly among a set of services. Requests are fair-queued +from frontend connections and load-balanced between backend connections. +Replies automatically return to the client that made the original request.

+

This device is part of the request-reply pattern. The frontend speaks to +clients and the backend speaks to services. You should use ZMQ_QUEUE with a +ZMQ_XREP socket for the frontend and a ZMQ_XREQ socket for the backend. +Other combinations are not documented.

+

Refer to zmq_socket(3) for a description of these socket types.

+
+

FORWARDER DEVICE

+
+

ZMQ_FORWARDER collects messages from a set of publishers and forwards these to +a set of subscribers. You will generally use this to bridge networks, e.g. read +on TCP unicast and forward on multicast.

+

This device is part of the publish-subscribe pattern. The frontend speaks to +publishers and the backend speaks to subscribers. You should use +ZMQ_FORWARDER with a ZMQ_SUB socket for the frontend and a ZMQ_PUB socket +for the backend. Other combinations are not documented.

+

Refer to zmq_socket(3) for a description of these socket types.

+
+

STREAMER DEVICE

+
+

ZMQ_STREAMER collects tasks from a set of pushers and forwards these to a set +of pullers. You will generally use this to bridge networks. Messages are +fair-queued from pushers and load-balanced to pullers.

+

This device is part of the pipeline pattern. The frontend speaks to pushers +and the backend speaks to pullers. You should use ZMQ_STREAMER with a +ZMQ_PULL socket for the frontend and a ZMQ_PUSH socket for the backend. +Other combinations are not documented.

+

Refer to zmq_socket(3) for a description of these socket types.

+
+

RETURN VALUE

+
+

The zmq_device() function always returns -1 and errno set to ETERM (the +ØMQ context associated with either of the specified sockets was terminated).

+
+

EXAMPLE

+
+
+
Creating a queue broker
+
+
//  Create frontend and backend sockets
+void *frontend = zmq_socket (context, ZMQ_XREP);
+assert (backend);
+void *backend = zmq_socket (context, ZMQ_XREQ);
+assert (frontend);
+//  Bind both sockets to TCP ports
+assert (zmq_bind (frontend, "tcp://*:5555") == 0);
+assert (zmq_bind (backend, "tcp://*:5556") == 0);
+//  Start a queue device
+zmq_device (ZMQ_QUEUE, frontend, backend);
+
+
+

SEE ALSO

+
+

zmq_bind(3) +zmq_connect(3) +zmq_socket(3) +zmq(7)

+
+

AUTHORS

+
+

This ØMQ manual page was written by Pieter Hintjens <ph@imatix.com>

+
+

RESOURCES

+
+

Main web site: http://www.zeromq.org/

+

Report bugs to the ØMQ development mailing list: <zeromq-dev@lists.zeromq.org>

+
+

COPYING

+
+

Free use of this software is granted under the terms of the GNU Lesser General +Public License (LGPL). For details see the files COPYING and COPYING.LESSER +included with the ØMQ distribution.

+
+
+
+ + + -- cgit v1.2.3