Provided by: libczmq-dev_4.1.0-2_amd64 bug


       zloop - Class for event-driven reactor


       //  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 'poll on FD zero'.
       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 '@interface' section in './../src/zloop.c'.


       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.

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


       From zloop_test method.

           //  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;

           //  Check if reader removed in timer is not called
           zloop_destroy (&loop);
           loop = zloop_new ();

           bool socket_event_called = false;
           zloop_reader (loop, output, s_socket_event1, &socket_event_called);
           zloop_timer (loop, 0, 1, s_timer_event5, output);

           zstr_send (input, "PING");

           zloop_start (loop);
           assert (!socket_event_called);

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

           zsock_destroy (&input);
           zsock_destroy (&output);

           #if defined (__WINDOWS__)


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


       Main web site:

       Report bugs to the email <[1]>


       Copyright (c) the 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.