<!-- GENERATED by docs/sphinx/bin/20-reference (p5) from reference/bundled/IO/Poll.md. Do not edit. -->

```{index} single: IO::Poll
```

# IO::Poll

Object interface to system poll call

## SYNOPSIS

```perl
use IO::Poll qw(POLLRDNORM POLLWRNORM POLLIN POLLHUP);

$poll = IO::Poll->new();

$poll->mask($input_handle => POLLIN);
$poll->mask($output_handle => POLLOUT);

$poll->poll($timeout);

$ev = $poll->events($input);
```

## DESCRIPTION

`IO::Poll` is a simple interface to the system level poll routine.

## METHODS

- mask ( IO \[, EVENT\_MASK \] )

    If EVENT\_MASK is given, then, if EVENT\_MASK is non-zero, IO is added to the
    list of file descriptors and the next call to poll will check for
    any event specified in EVENT\_MASK. If EVENT\_MASK is zero then IO will be
    removed from the list of file descriptors.

    If EVENT\_MASK is not given then the return value will be the current
    event mask value for IO.

- poll ( \[ TIMEOUT \] )

    Call the system level poll routine. If TIMEOUT is not specified then the
    call will block. Returns the number of handles which had events
    happen, or -1 on error.

- events ( IO )

    Returns the event mask which represents the events that happened on IO
    during the last call to `poll`.

- remove ( IO )

    Remove IO from the list of file descriptors for the next poll.

- handles( \[ EVENT\_MASK \] )

    Returns a list of handles. If EVENT\_MASK is not given then a list of all
    handles known will be returned. If EVENT\_MASK is given then a list
    of handles will be returned which had one of the events specified by
    EVENT\_MASK happen during the last call to `poll`.

## SEE ALSO

[poll(2)](http://man.he.net/man2/poll), [IO::Handle](Handle.md), [IO::Select](Select.md)

## AUTHOR

Graham Barr. Currently maintained by the Perl Porters.  Please report all
bugs at [https://github.com/Perl/perl5/issues](https://github.com/Perl/perl5/issues).

## COPYRIGHT

Copyright (c) 1997-8 Graham Barr <gbarr@pobox.com>. All rights reserved.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.