# phpman > man > IO::Poll

## NAME
    [IO::Poll](https://www.chedong.com/phpMan.php/perldoc/IO%3A%3APoll/markdown) - Object interface to system poll call

## SYNOPSIS
        use [IO::Poll](https://www.chedong.com/phpMan.php/perldoc/IO%3A%3APoll/markdown) qw(POLLRDNORM POLLWRNORM POLLIN POLLHUP);

        $poll = [IO::Poll](https://www.chedong.com/phpMan.php/perldoc/IO%3A%3APoll/markdown)->new();

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

        $poll->poll($timeout);

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

## DESCRIPTION
    "[IO::Poll](https://www.chedong.com/phpMan.php/perldoc/IO%3A%3APoll/markdown)" 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
        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 ti "poll"

## SEE ALSO
### poll

## AUTHOR
    Graham Barr. Currently maintained by the Perl Porters. Please report all bugs to
    <<perlbug@perl.org>>.

## 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.