jyoung/phonelibs/zmq/aarch64-linux/share/man/man3/zloop.3

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.\"     Title: zloop
.\"    Author: [see the "AUTHORS" section]
.\" Generator: DocBook XSL Stylesheets v1.76.1 <http://docbook.sf.net/>
.\"      Date: 12/31/2016
.\"    Manual: CZMQ Manual
.\"    Source: CZMQ 4.0.2
.\"  Language: English
.\"
.TH "ZLOOP" "3" "12/31/2016" "CZMQ 4\&.0\&.2" "CZMQ Manual"
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.SH "NAME"
zloop \- event\-driven reactor
.SH "SYNOPSIS"
.sp
.nf
//  This is a stable class, and may not change except for emergencies\&. It
//  is provided in stable builds\&.
// Callback function for reactor socket activity
typedef int (zloop_reader_fn) (
    zloop_t *loop, zsock_t *reader, void *arg);

// Callback function for reactor events (low\-level)
typedef int (zloop_fn) (
    zloop_t *loop, zmq_pollitem_t *item, void *arg);

// Callback for reactor timer events
typedef int (zloop_timer_fn) (
    zloop_t *loop, int timer_id, void *arg);

//  Create a new zloop reactor
CZMQ_EXPORT zloop_t *
    zloop_new (void);

//  Destroy a reactor
CZMQ_EXPORT void
    zloop_destroy (zloop_t **self_p);

//  Register socket reader with the reactor\&. When the reader has messages,
//  the reactor will call the handler, passing the arg\&. Returns 0 if OK, \-1
//  if there was an error\&. If you register the same socket more than once,
//  each instance will invoke its corresponding handler\&.
CZMQ_EXPORT int
    zloop_reader (zloop_t *self, zsock_t *sock, zloop_reader_fn handler, void *arg);

//  Cancel a socket reader from the reactor\&. If multiple readers exist for
//  same socket, cancels ALL of them\&.
CZMQ_EXPORT void
    zloop_reader_end (zloop_t *self, zsock_t *sock);

//  Configure a registered reader to ignore errors\&. If you do not set this,
//  then readers that have errors are removed from the reactor silently\&.
CZMQ_EXPORT void
    zloop_reader_set_tolerant (zloop_t *self, zsock_t *sock);

//  Register low\-level libzmq pollitem with the reactor\&. When the pollitem
//  is ready, will call the handler, passing the arg\&. Returns 0 if OK, \-1
//  if there was an error\&. If you register the pollitem more than once, each
//  instance will invoke its corresponding handler\&. A pollitem with
//  socket=NULL and fd=0 means \*(Aqpoll on FD zero\*(Aq\&.
CZMQ_EXPORT int
    zloop_poller (zloop_t *self, zmq_pollitem_t *item, zloop_fn handler, void *arg);

//  Cancel a pollitem from the reactor, specified by socket or FD\&. If both
//  are specified, uses only socket\&. If multiple poll items exist for same
//  socket/FD, cancels ALL of them\&.
CZMQ_EXPORT void
    zloop_poller_end (zloop_t *self, zmq_pollitem_t *item);

//  Configure a registered poller to ignore errors\&. If you do not set this,
//  then poller that have errors are removed from the reactor silently\&.
CZMQ_EXPORT void
    zloop_poller_set_tolerant (zloop_t *self, zmq_pollitem_t *item);

//  Register a timer that expires after some delay and repeats some number of
//  times\&. At each expiry, will call the handler, passing the arg\&. To run a
//  timer forever, use 0 times\&. Returns a timer_id that is used to cancel the
//  timer in the future\&. Returns \-1 if there was an error\&.
CZMQ_EXPORT int
    zloop_timer (zloop_t *self, size_t delay, size_t times, zloop_timer_fn handler, void *arg);

//  Cancel a specific timer identified by a specific timer_id (as returned by
//  zloop_timer)\&.
CZMQ_EXPORT int
    zloop_timer_end (zloop_t *self, int timer_id);

//  Register a ticket timer\&. Ticket timers are very fast in the case where
//  you use a lot of timers (thousands), and frequently remove and add them\&.
//  The main use case is expiry timers for servers that handle many clients,
//  and which reset the expiry timer for each message received from a client\&.
//  Whereas normal timers perform poorly as the number of clients grows, the
//  cost of ticket timers is constant, no matter the number of clients\&. You
//  must set the ticket delay using zloop_set_ticket_delay before creating a
//  ticket\&. Returns a handle to the timer that you should use in
//  zloop_ticket_reset and zloop_ticket_delete\&.
CZMQ_EXPORT void *
    zloop_ticket (zloop_t *self, zloop_timer_fn handler, void *arg);

//  Reset a ticket timer, which moves it to the end of the ticket list and
//  resets its execution time\&. This is a very fast operation\&.
CZMQ_EXPORT void
    zloop_ticket_reset (zloop_t *self, void *handle);

//  Delete a ticket timer\&. We do not actually delete the ticket here, as
//  other code may still refer to the ticket\&. We mark as deleted, and remove
//  later and safely\&.
CZMQ_EXPORT void
    zloop_ticket_delete (zloop_t *self, void *handle);

//  Set the ticket delay, which applies to all tickets\&. If you lower the
//  delay and there are already tickets created, the results are undefined\&.
CZMQ_EXPORT void
    zloop_set_ticket_delay (zloop_t *self, size_t ticket_delay);

//  Set hard limit on number of timers allowed\&. Setting more than a small
//  number of timers (10\-100) can have a dramatic impact on the performance
//  of the reactor\&. For high\-volume cases, use ticket timers\&. If the hard
//  limit is reached, the reactor stops creating new timers and logs an
//  error\&.
CZMQ_EXPORT void
    zloop_set_max_timers (zloop_t *self, size_t max_timers);

//  Set verbose tracing of reactor on/off\&. The default verbose setting is
//  off (false)\&.
CZMQ_EXPORT void
    zloop_set_verbose (zloop_t *self, bool verbose);

//  By default the reactor stops if the process receives a SIGINT or SIGTERM
//  signal\&. This makes it impossible to shut\-down message based architectures
//  like zactors\&. This method lets you switch off break handling\&. The default
//  nonstop setting is off (false)\&.
CZMQ_EXPORT void
    zloop_set_nonstop (zloop_t *self, bool nonstop);

//  Start the reactor\&. Takes control of the thread and returns when the 0MQ
//  context is terminated or the process is interrupted, or any event handler
//  returns \-1\&. Event handlers may register new sockets and timers, and
//  cancel sockets\&. Returns 0 if interrupted, \-1 if canceled by a handler\&.
CZMQ_EXPORT int
    zloop_start (zloop_t *self);

//  Self test of this class\&.
CZMQ_EXPORT void
    zloop_test (bool verbose);

Please add \*(Aq@interface\*(Aq section in \*(Aq\&./\&.\&./src/zloop\&.c\*(Aq\&.
.fi
.SH "DESCRIPTION"
.sp
The zloop class provides an event\-driven reactor pattern\&. The reactor handles zmq_pollitem_t items (pollers or writers, sockets or fds), and once\-off or repeated timers\&. Its resolution is 1 msec\&. It uses a tickless timer to reduce CPU interrupts in inactive processes\&.
.sp
Please add \fI@discuss\fR section in \fI\&./\&.\&./src/zloop\&.c\fR\&.
.SH "EXAMPLE"
.PP
\fBFrom zloop_test method\fR. 
.sp
.if n \{\
.RS 4
.\}
.nf
//  Create two PAIR sockets and connect over inproc
zsock_t *output = zsock_new (ZMQ_PAIR);
assert (output);
zsock_bind (output, "inproc://zloop\&.test");

zsock_t *input = zsock_new (ZMQ_PAIR);
assert (input);
zsock_connect (input, "inproc://zloop\&.test");

zloop_t *loop = zloop_new ();
assert (loop);
zloop_set_verbose (loop, verbose);

//  Create a timer that will be cancelled
int timer_id = zloop_timer (loop, 1000, 1, s_timer_event, NULL);
zloop_timer (loop, 5, 1, s_cancel_timer_event, &timer_id);

//  After 20 msecs, send a ping message to output3
zloop_timer (loop, 20, 1, s_timer_event, output);

//  Set up some tickets that will never expire
zloop_set_ticket_delay (loop, 10000);
void *ticket1 = zloop_ticket (loop, s_timer_event, NULL);
void *ticket2 = zloop_ticket (loop, s_timer_event, NULL);
void *ticket3 = zloop_ticket (loop, s_timer_event, NULL);

//  When we get the ping message, end the reactor
rc = zloop_reader (loop, input, s_socket_event, NULL);
assert (rc == 0);
zloop_reader_set_tolerant (loop, input);
zloop_start (loop);

zloop_ticket_delete (loop, ticket1);
zloop_ticket_delete (loop, ticket2);
zloop_ticket_delete (loop, ticket3);

//  Check whether loop properly ignores zsys_interrupted flag
//  when asked to
zloop_destroy (&loop);
loop = zloop_new ();

bool timer_event_called = false;
zloop_timer (loop, 1, 1, s_timer_event3, &timer_event_called);

zsys_interrupted = 1;
zloop_start (loop);
//  zloop returns immediately without giving any handler a chance to run
assert (!timer_event_called);

zloop_set_nonstop (loop, true);
zloop_start (loop);
//  zloop runs the handler which will terminate the loop
assert (timer_event_called);
zsys_interrupted = 0;

//  cleanup
zloop_destroy (&loop);
assert (loop == NULL);

zsock_destroy (&input);
zsock_destroy (&output);
.fi
.if n \{\
.RE
.\}
.sp
.SH "AUTHORS"
.sp
The czmq manual was written by the authors in the AUTHORS file\&.
.SH "RESOURCES"
.sp
Main web site: \m[blue]\fB\%\fR\m[]
.sp
Report bugs to the email <\m[blue]\fBzeromq\-dev@lists\&.zeromq\&.org\fR\m[]\&\s-2\u[1]\d\s+2>
.SH "COPYRIGHT"
.sp
Copyright (c) the Contributors as noted in the AUTHORS file\&. This file is part of CZMQ, the high\-level C binding for 0MQ: http://czmq\&.zeromq\&.org\&. 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 http://mozilla\&.org/MPL/2\&.0/\&. LICENSE included with the czmq distribution\&.
.SH "NOTES"
.IP " 1." 4
zeromq-dev@lists.zeromq.org
.RS 4
\%mailto:zeromq-dev@lists.zeromq.org
.RE