# Synchronized subscriber in Perl
use strict;
use warnings;
use v5.10;
use ZMQ::FFI;
use ZMQ::FFI::Constants qw(ZMQ_SUB ZMQ_REQ ZMQ_RCVHWM);
my $context = ZMQ::FFI->new();
# First, connect our subscriber socket
my $subscriber = $context->socket(ZMQ_SUB);
$subscriber->set(ZMQ_RCVHWM, 'int', 0);
$subscriber->connect('tcp://localhost:5561');
$subscriber->subscribe('');
# 0MQ is so fast, we need to wait a while…
sleep 3;
# Second, synchronize with publisher
my $syncclient = $context->socket(ZMQ_REQ);
$syncclient->connect('tcp://localhost:5562');
# send a synchronization request
$syncclient->send('');
# wait for synchronization reply
$syncclient->recv();
# Third, get our updates and report how many we got
my $update_nbr = 0;
while (1) {
last if $subscriber->recv() eq "END";
$update_nbr++;
}
say "Received $update_nbr updates";