---
name: "ZeroMQ::Poller"
section: "3pm"
platform: "linux"
package: "libzeromq-perl"
version: "0.23-1+b2"
release: "Debian 8 (Jessie)"
platforms: ["linux"]
url: "https://new.carta.tech/ZeroMQ::Poller"
---

# ZeroMQ::Poller(3pm)

Convenient socket polling object

## NAME

ZeroMQ::Poller - Convenient socket polling object

## SYNOPSIS

```
  use ZeroMQ qw/:all/;
  my $cxt = ZeroMQ::Context->new()
  my $sock = ZeroMQ::Socket->new($cxt, ZMQ_REP);
  $sock->bind("inproc://amazingsocket");
  my $poller = ZeroMQ::Poller->new(
    {
      name      => 'amazing',
      socket    => $sock,
      events    => ZMQ_POLLIN,
      callback  => sub { do_something_amazing },
    },
  );
  $poller->poll();
  do_another_amazing_thing() if $poller->has_event(0);
  do_a_third_amazing_thing() if $poller->has_event('amazing');
```

## DESCRIPTION

A `"ZeroMQ::Poller"` watches zero or more sockets for events and signals that these have occurred in several ways.  Given a list of sockets and events to watch for, it can directly invoke a callback or simply raise a flag.

## METHODS

### new(@poll\_items)

Creates a new `"ZeroMQ::Poller"`

The constructor accepts a list of hash references ("poll items"), each of which specifies a socket or file descriptor to watch and what to watch it for.  In addition, each poll item may specify a callback to invoke or a name by which it may be queried. The accepted keys are:

- socket

  Contains the `"ZeroMQ::Socket"` item to poll.

- fd

  Contains the file descriptor to poll.  One of `"socket"` or `"fd"` is required; `"socket"` has precedence.

- events

  Some combination of `"ZMQ_POLLIN"`, `"ZMQ_POLLOUT"`, and `"ZMQ_POLLERR"`; the events to trap.

- callback

  A coderef taking no arguments and emitting no return value, invoked when the specified events occur on the socket or file descriptor.  Optional.

- name

  A string, naming the poll item for later use with `"has_event"`.

### poll($timeout)

Blocks until there is activity or the given timeout is reached.  If no timeout or a negative timeout is specified, blocks indefinitely.  If a timeout is given, it is interpreted as microseconds.

### has\_event($index)

### has\_event($name)

Returns true if the poll item at the given index or with the given name reported activity during the last call to `"poll"`.