# phpman > perldoc > List::Util::XS

## NAME
    [List::Util::XS](https://www.chedong.com/phpMan.php/perldoc/List%3A%3AUtil%3A%3AXS/markdown) - Indicate if [List::Util](https://www.chedong.com/phpMan.php/perldoc/List%3A%3AUtil/markdown) was compiled with a C compiler

## SYNOPSIS
        use [List::Util::XS](https://www.chedong.com/phpMan.php/perldoc/List%3A%3AUtil%3A%3AXS/markdown) 1.20;

## DESCRIPTION
    "[List::Util::XS](https://www.chedong.com/phpMan.php/perldoc/List%3A%3AUtil%3A%3AXS/markdown)" can be used as a dependency to ensure [List::Util](https://www.chedong.com/phpMan.php/perldoc/List%3A%3AUtil/markdown) was installed using a C
    compiler and that the XS version is installed.

    During installation $[List::Util::XS::VERSION](https://www.chedong.com/phpMan.php/perldoc/List%3A%3AUtil%3A%3AXS%3A%3AVERSION/markdown) will be set to "undef" if the XS was not compiled.

    Starting with release 1.23_03, Scalar-List-Util is always using the XS implementation, but for
    backwards compatibility, we still ship the "[List::Util::XS](https://www.chedong.com/phpMan.php/perldoc/List%3A%3AUtil%3A%3AXS/markdown)" module which just loads
    "[List::Util](https://www.chedong.com/phpMan.php/perldoc/List%3A%3AUtil/markdown)".

## SEE ALSO
    [Scalar::Util](https://www.chedong.com/phpMan.php/perldoc/Scalar%3A%3AUtil/markdown), [List::Util](https://www.chedong.com/phpMan.php/perldoc/List%3A%3AUtil/markdown), [List::MoreUtils](https://www.chedong.com/phpMan.php/perldoc/List%3A%3AMoreUtils/markdown)

## COPYRIGHT
    Copyright (c) 2008 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.