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diff --git a/doc/zmq_proxy.3 b/doc/zmq_proxy.3 new file mode 100644 index 0000000..f3017f9 --- /dev/null +++ b/doc/zmq_proxy.3 @@ -0,0 +1,89 @@ +'\" t +.\" Title: zmq_proxy +.\" Author: [see the "AUTHORS" section] +.\" Generator: DocBook XSL Stylesheets v1.76.1 <http://docbook.sf.net/> +.\" Date: 10/14/2014 +.\" Manual: 0MQ Manual +.\" Source: 0MQ 4.0.5 +.\" Language: English +.\" +.TH "ZMQ_PROXY" "3" "10/14/2014" "0MQ 4\&.0\&.5" "0MQ Manual" +.\" ----------------------------------------------------------------- +.\" * Define some portability stuff +.\" ----------------------------------------------------------------- +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" http://bugs.debian.org/507673 +.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" ----------------------------------------------------------------- +.\" * set default formatting +.\" ----------------------------------------------------------------- +.\" disable hyphenation +.nh +.\" disable justification (adjust text to left margin only) +.ad l +.\" ----------------------------------------------------------------- +.\" * MAIN CONTENT STARTS HERE * +.\" ----------------------------------------------------------------- +.SH "NAME" +zmq_proxy \- start built\-in 0MQ proxy +.SH "SYNOPSIS" +.sp +\fBint zmq_proxy (const void \fR\fB\fI*frontend\fR\fR\fB, const void \fR\fB\fI*backend\fR\fR\fB, const void \fR\fB\fI*capture\fR\fR\fB);\fR +.SH "DESCRIPTION" +.sp +The \fIzmq_proxy()\fR function starts the built\-in 0MQ proxy in the current application thread\&. +.sp +The proxy 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\&. The direction is conceptual only; the proxy is fully symmetric and there is no technical difference between frontend and backend\&. +.sp +Before calling \fIzmq_proxy()\fR you must set any socket options, and connect or bind both frontend and backend sockets\&. The two conventional proxy models are: +.sp +\fIzmq_proxy()\fR runs in the current thread and returns only if/when the current context is closed\&. +.sp +If the capture socket is not NULL, the proxy shall send all messages, received on both frontend and backend, to the capture socket\&. The capture socket should be a \fIZMQ_PUB\fR, \fIZMQ_DEALER\fR, \fIZMQ_PUSH\fR, or \fIZMQ_PAIR\fR socket\&. +.sp +Refer to \fBzmq_socket\fR(3) for a description of the available socket types\&. +.SH "EXAMPLE USAGE" +.SS "Shared Queue" +.sp +When the frontend is a ZMQ_ROUTER socket, and the backend is a ZMQ_DEALER socket, the proxy shall act as a shared queue that collects requests from a set of clients, and distributes these fairly among a set of services\&. Requests shall be fair\-queued from frontend connections and distributed evenly across backend connections\&. Replies shall automatically return to the client that made the original request\&. +.SS "Forwarder" +.sp +When the frontend is a ZMQ_XSUB socket, and the backend is a ZMQ_XPUB socket, the proxy shall act as a message forwarder that collects messages from a set of publishers and forwards these to a set of subscribers\&. This may be used to bridge networks transports, e\&.g\&. read on tcp:// and forward on pgm://\&. +.SS "Streamer" +.sp +When the frontend is a ZMQ_PULL socket, and the backend is a ZMQ_PUSH socket, the proxy shall collect tasks from a set of clients and forwards these to a set of workers using the pipeline pattern\&. +.SH "RETURN VALUE" +.sp +The \fIzmq_proxy()\fR function always returns \-1 and \fIerrno\fR set to \fBETERM\fR (the 0MQ \fIcontext\fR associated with either of the specified sockets was terminated)\&. +.SH "EXAMPLE" +.PP +\fBCreating a shared queue proxy\fR. +.sp +.if n \{\ +.RS 4 +.\} +.nf +// Create frontend and backend sockets +void *frontend = zmq_socket (context, ZMQ_ROUTER); +assert (backend); +void *backend = zmq_socket (context, ZMQ_DEALER); +assert (frontend); +// Bind both sockets to TCP ports +assert (zmq_bind (frontend, "tcp://*:5555") == 0); +assert (zmq_bind (backend, "tcp://*:5556") == 0); +// Start the queue proxy, which runs until ETERM +zmq_proxy (frontend, backend, NULL); +.fi +.if n \{\ +.RE +.\} +.sp +.SH "SEE ALSO" +.sp +\fBzmq_bind\fR(3) \fBzmq_connect\fR(3) \fBzmq_socket\fR(3) \fBzmq\fR(7) +.SH "AUTHORS" +.sp +This page was written by the 0MQ community\&. To make a change please read the 0MQ Contribution Policy at \m[blue]\fBhttp://www\&.zeromq\&.org/docs:contributing\fR\m[]\&. |