*int zmq_socket_monitor (void '*socket', char * '*addr', int 'events');
該api用於創建一個監聽器, 用於監聽socket中的事件.
其事件有
MQ_EVENT_CONNECTED: connection established
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_EVENT_CONNECTED' event triggers when a connection has been established
to a remote peer. This can happen either synchronous or asynchronous.
Value is the FD of the newly connected socket.
ZMQ_EVENT_CONNECT_DELAYED: synchronous connect failed, it's being polled
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_EVENT_CONNECT_DELAYED' event triggers when an immediate connection
attempt is delayed and its completion is being polled for.
Value has no meaning.
ZMQ_EVENT_CONNECT_RETRIED: asynchronous connect / reconnection attempt
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_EVENT_CONNECT_RETRIED' event triggers when a connection attempt
is being handled by reconnect timer. The reconnect interval's recomputed
for each attempt.
Value is the reconnect interval.
ZMQ_EVENT_LISTENING: socket bound to an address, ready to accept connections
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_EVENT_LISTENING' event triggers when a socket's successfully bound
to a an interface.
Value is the FD of the newly bound socket.
ZMQ_EVENT_BIND_FAILED: socket could not bind to an address
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_EVENT_BIND_FAILED' event triggers when a socket could not bind to
a given interface.
Value is the errno generated by the bind call.
ZMQ_EVENT_ACCEPTED: connection accepted to bound interface
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_EVENT_ACCEPTED' event triggers when a connection from a remote peer
has been established with a socket's listen address.
Value is the FD of the accepted socket.
ZMQ_EVENT_ACCEPT_FAILED: could not accept client connection
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_EVENT_ACCEPT_FAILED' event triggers when a connection attempt to
a socket's bound address fails.
Value is the errno generated by accept.
ZMQ_EVENT_CLOSED: connection closed
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_EVENT_CLOSED' event triggers when a connection's underlying descriptor
has been closed.
Value is the former FD of the for the closed socket. FD has been closed already!
ZMQ_EVENT_CLOSE_FAILED: connection couldn't be closed
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_EVENT_CLOSE_FAILED' event triggers when a descriptor could not be
released back to the OS. Implementation note: ONLY FOR IPC SOCKETS.
Value is the errno generated by unlink.
ZMQ_EVENT_DISCONNECTED: broken session
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_EVENT_DISCONNECTED' event triggers when the stream engine (tcp and ipc
specific) detects a corrupted / broken session.
Value is the FD of the socket.
example:
#include <stdio.h>
#include <zmq.h>
#include <pthread.h>
#include <string.h>
#include <assert.h>
static int read_msg(void* s, zmq_event_t* event, char* ep)
{
int rc ;
zmq_msg_t msg1; // binary part
zmq_msg_init (&msg1);
zmq_msg_t msg2; // address part
zmq_msg_init (&msg2);
rc = zmq_msg_recv (&msg1, s, 0);
if (rc == -1 && zmq_errno() == ETERM)
return 1 ;
assert (rc != -1);
assert (zmq_msg_more(&msg1) != 0);
rc = zmq_msg_recv (&msg2, s, 0);
if (rc == -1 && zmq_errno() == ETERM)
return 1;
assert (rc != -1);
assert (zmq_msg_more(&msg2) == 0);
// copy binary data to event struct
const char* data = (char*)zmq_msg_data(&msg1);
memcpy(&(event->event), data, sizeof(event->event));
memcpy(&(event->value), data+sizeof(event->event), sizeof(event->value));
// copy address part
const size_t len = zmq_msg_size(&msg2) ;
ep = memcpy(ep, zmq_msg_data(&msg2), len);
*(ep + len) = 0 ;
return 0 ;
}
// REP socket monitor thread
static void *rep_socket_monitor (void *ctx)
{
zmq_event_t event;
static char addr[1025] ;
int rc;
printf("starting monitor...\n");
void *s = zmq_socket (ctx, ZMQ_PAIR);
assert (s);
rc = zmq_connect (s, "inproc://monitor.rep");
assert (rc == 0);
while (!read_msg(s, &event, addr)) {
switch (event.event) {
case ZMQ_EVENT_LISTENING:
printf ("listening socket descriptor %d\n", event.value);
printf ("listening socket address %s\n", addr);
break;
case ZMQ_EVENT_ACCEPTED:
printf ("accepted socket descriptor %d\n", event.value);
printf ("accepted socket address %s\n", addr);
break;
case ZMQ_EVENT_CLOSE_FAILED:
printf ("socket close failure error code %d\n", event.value);
printf ("socket address %s\n", addr);
break;
case ZMQ_EVENT_CLOSED:
printf ("closed socket descriptor %d\n", event.value);
printf ("closed socket address %s\n", addr);
break;
case ZMQ_EVENT_DISCONNECTED:
printf ("disconnected socket descriptor %d\n", event.value);
printf ("disconnected socket address %s\n", addr);
break;
}
}
zmq_close (s);
return NULL;
}
int main()
{
const char* addr = "tcp://127.0.0.1:6666" ;
pthread_t thread ;
// Create the infrastructure
void *ctx = zmq_init (1);
assert (ctx);
// REP socket
void* rep = zmq_socket (ctx, ZMQ_REP);
assert (rep);
// REP socket monitor, all events
int rc = zmq_socket_monitor (rep, "inproc://monitor.rep", ZMQ_EVENT_ALL);
assert (rc == 0);
rc = pthread_create (&thread, NULL, rep_socket_monitor, ctx);
assert (rc == 0);
rc = zmq_bind (rep, addr);
assert (rc == 0);
// Allow some time for event detection
zmq_sleep (1);
// Close the REP socket
rc = zmq_close (rep);
assert (rc == 0);
zmq_term (ctx);
return 0 ;
}