# phpman > perldoc > POE::Resource::Extrefs

## NAME
    [POE::Resource::Extrefs](https://www.chedong.com/phpMan.php/perldoc/POE%3A%3AResource%3A%3AExtrefs/markdown) - internal reference counts manager for [POE::Kernel](https://www.chedong.com/phpMan.php/perldoc/POE%3A%3AKernel/markdown)

## SYNOPSIS
    There is no public API.

## DESCRIPTION
    [POE::Resource::Extrefs](https://www.chedong.com/phpMan.php/perldoc/POE%3A%3AResource%3A%3AExtrefs/markdown) is a mix-in class for [POE::Kernel](https://www.chedong.com/phpMan.php/perldoc/POE%3A%3AKernel/markdown). It provides the features to manage
    session reference counts, specifically the ones that applications may use.
    [POE::Resource::Extrefs](https://www.chedong.com/phpMan.php/perldoc/POE%3A%3AResource%3A%3AExtrefs/markdown) is used internally by [POE::Kernel](https://www.chedong.com/phpMan.php/perldoc/POE%3A%3AKernel/markdown), so it has no public interface.

## SEE ALSO
    See "Public Reference Counters" in [POE::Kernel](https://www.chedong.com/phpMan.php/perldoc/POE%3A%3AKernel/markdown) for the public extref API.

    See "Resources" in [POE::Kernel](https://www.chedong.com/phpMan.php/perldoc/POE%3A%3AKernel/markdown) for public information about POE resources.

    See [POE::Resource](https://www.chedong.com/phpMan.php/perldoc/POE%3A%3AResource/markdown) for general discussion about resources and the classes that manage them.

## BUGS
    Reference counters have no ownership information, so one entity's reference counts may conflict
    with another's. This is usually not a problem if all entities behave.

AUTHORS & COPYRIGHTS
    Please see POE for more information about authors and contributors.