zmonitor(3)

zmonitor(3)

CZMQ Manual - CZMQ/2.2.1

+ Table of Contents

Name

zmonitor - socket event monitor

Synopsis

//  Create a new socket monitor
CZMQ_EXPORT zmonitor_t *
    zmonitor_new (zctx_t *ctx, void *socket, int events);

//  Destroy a socket monitor
CZMQ_EXPORT void
    zmonitor_destroy (zmonitor_t **self_p);

//  Receive a status message from the monitor; if no message arrives within
//  500 msec, or the call was interrupted, returns NULL.
CZMQ_EXPORT zmsg_t *
    zmonitor_recv (zmonitor_t *self);

//  Get the ZeroMQ socket, for polling
CZMQ_EXPORT void *
    zmonitor_socket (zmonitor_t *self);

//  Enable verbose tracing of commands and activity
CZMQ_EXPORT void
    zmonitor_set_verbose (zmonitor_t *self, bool verbose);

// Self test of this class
CZMQ_EXPORT void
    zmonitor_test (bool verbose);

Description

The zmonitor class provides an API for obtaining socket events such as connected, listen, disconnected, etc. Socket events are only available for sockets connecting or bound to ipc:// and tcp:// endpoints.

This class wraps the ZMQ socket monitor API, see zmq_socket_monitor for details. Currently this class requires libzmq v4.0 or later and is empty on older versions of libzmq.

Example

From zmonitor_test method

 zctx_t *ctx = zctx_new ();
 bool result;

 void *sink = zsocket_new (ctx, ZMQ_PULL);
 zmonitor_t *sinkmon = zmonitor_new (ctx,
 sink, ZMQ_EVENT_LISTENING | ZMQ_EVENT_ACCEPTED);
 zmonitor_set_verbose (sinkmon, verbose);

 // Check sink is now listening
 zsocket_bind (sink, "tcp://*:5555");
 result = s_check_event (sinkmon, ZMQ_EVENT_LISTENING);
 assert (result);

 void *source = zsocket_new (ctx, ZMQ_PUSH);
 zmonitor_t *sourcemon = zmonitor_new (ctx,
 source, ZMQ_EVENT_CONNECTED | ZMQ_EVENT_DISCONNECTED);
 zmonitor_set_verbose (sourcemon, verbose);
 zsocket_connect (source, "tcp://localhost:5555");

 // Check source connected to sink
 result = s_check_event (sourcemon, ZMQ_EVENT_CONNECTED);
 assert (result);

 // Check sink accepted connection
 result = s_check_event (sinkmon, ZMQ_EVENT_ACCEPTED);
 assert (result);

 // Destroy sink to trigger a disconnect event on the source
 // PH: disabled since this causes an access violation in
 // zmonitor_destroy as the socket is no longer valid.
// zsocket_destroy (ctx, sink);
// result = s_check_event (sourcemon, ZMQ_EVENT_DISCONNECTED);
// assert (result);

 zmonitor_destroy (&sinkmon);
 zmonitor_destroy (&sourcemon);  zctx_destroy (&ctx);

See also

czmq(7)

Authors

The CZMQ manual was written by Pieter Hintjens<moc.xitami|hp#moc.xitami|hp>.

Resources

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

Report bugs to the ØMQ development mailing list: <gro.qmorez.stsil|ved-qmorez#gro.qmorez.stsil|ved-qmorez>

Copyright

Copyright (c) 1991-2014 iMatix and Contributors. License LGPLv3+: GNU LGPL 3 or later <http://gnu.org/licenses/lgpl.html>. This is free software: you are free to change it and redistribute it. There is NO WARRANTY, to the extent permitted by law. For details see the files COPYING and COPYING.LESSER included with the CZMQ distribution.