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Man Pages

Manual Reference Pages  -  ZPOLLER (3)

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zpoller - trivial socket poller class



//  Create new poller; the reader can be a libzmq socket (void *), a zsock_t
//  instance, or a zactor_t instance.
CZMQ_EXPORT zpoller_t *
    zpoller_new (void *reader, ...);

// Destroy a poller CZMQ_EXPORT void zpoller_destroy (zpoller_t **self_p);

// Add a reader to be polled. Returns 0 if OK, -1 on failure. The reader may // be a libzmq void * socket, a zsock_t instance, or a zactor_t instance. CZMQ_EXPORT int zpoller_add (zpoller_t *self, void *reader);

// Remove a reader from the poller; returns 0 if OK, -1 on failure. The // reader may be a libzmq void * socket, a zsock_t instance, or a zactor_t // instance. CZMQ_EXPORT int zpoller_remove (zpoller_t *self, void *reader);

// Poll the registered readers for I/O, return first reader that has input. // The reader will be a libzmq void * socket, or a zsock_t or zactor_t // instance as specified in zpoller_new/zpoller_add. The timeout should be // zero or greater, or -1 to wait indefinitely. Socket priority is defined // by their order in the poll list. If you need a balanced poll, use the low // level zmq_poll method directly. If the poll call was interrupted (SIGINT), // or the ZMQ context was destroyed, or the timeout expired, returns NULL. // You can test the actual exit condition by calling zpoller_expired () and // zpoller_terminated (). The timeout is in msec. CZMQ_EXPORT void * zpoller_wait (zpoller_t *self, int timeout);

// Return true if the last zpoller_wait () call ended because the timeout // expired, without any error. CZMQ_EXPORT bool zpoller_expired (zpoller_t *self);

// Return true if the last zpoller_wait () call ended because the process // was interrupted, or the parent context was destroyed. CZMQ_EXPORT bool zpoller_terminated (zpoller_t *self);

// Ignore zsys_interrupted flag in this poller. By default, a zpoller_wait will // return immediately if detects zsys_interrupted is set to something other than // zero. Calling zpoller_ignore_interrupts will supress this behavior.

CZMQ_EXPORT void zpoller_ignore_interrupts(zpoller_t *self);

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


The zpoller class provides a minimalist interface to ZeroMQ\(cqs zmq_poll API, for the very common case of reading from a number of sockets. It does not provide polling for output, nor polling on file handles. If you need either of these, use the zmq_poll API directly.

Please add @discuss section in ../src/zpoller.c.


From zpoller_test method.

//  Create a few sockets
zsock_t *vent = zsock_new (ZMQ_PUSH);
assert (vent);
int port_nbr = zsock_bind (vent, "tcp://*");
assert (port_nbr != -1);
zsock_t *sink = zsock_new (ZMQ_PULL);
assert (sink);
int rc = zsock_connect (sink, "tcp://", port_nbr);
assert (rc != -1);
zsock_t *bowl = zsock_new (ZMQ_PULL);
assert (bowl);
zsock_t *dish = zsock_new (ZMQ_PULL);
assert (dish);

// Set-up poller zpoller_t *poller = zpoller_new (bowl, dish, NULL); assert (poller);

// Add a reader to the existing poller rc = zpoller_add (poller, sink); assert (rc == 0);

zstr_send (vent, "Hello, World");

// We expect a message only on the sink zsock_t *which = (zsock_t *) zpoller_wait (poller, -1); assert (which == sink); assert (zpoller_expired (poller) == false); assert (zpoller_terminated (poller) == false); char *message = zstr_recv (which); assert (streq (message, "Hello, World")); zstr_free (&message);

// Stop polling reader rc = zpoller_remove (poller, sink); assert (rc == 0);

// Check we can poll an FD rc = zsock_connect (bowl, "tcp://", port_nbr); assert (rc != -1); SOCKET fd = zsock_fd (bowl); rc = zpoller_add (poller, (void *) &fd); assert (rc != -1); zstr_send (vent, "Hello again, world"); assert (zpoller_wait (poller, 500) == &fd);

// Check whether poller properly ignores zsys_interrupted flag // when asked to zsys_interrupted = 1; zpoller_wait (poller, 0); assert (zpoller_terminated (poller)); zpoller_ignore_interrupts (poller); zpoller_wait (poller, 0); assert (!zpoller_terminated (poller)); zsys_interrupted = 0;

// Destroy poller and sockets zpoller_destroy (&poller);

zsock_destroy (&vent); zsock_destroy (&sink); zsock_destroy (&bowl); zsock_destroy (&dish);


The czmq manual was written by the authors in the AUTHORS file.


Main web site: \m[blue] \m[]

Report bugs to the email <\m[blue]\m[][1]>


Copyright (c) 1991-2012 iMatix Corporation -- Copyright other contributors as noted in the AUTHORS file. This file is part of CZMQ, the high-level C binding for 0MQ: This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at LICENSE included with the czmq distribution.


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CZMQ 3&.0&.1 ZPOLLER (3) 06/01/2015

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