Ref::Util::XS is the XS implementation of Ref::Util, which provides several functions to help identify references in a more convenient way than the usual approach of examining the return value of 'ref'.

You should use Ref::Util::XS by installing Ref::Util itself: if the system you install it on has a C compiler available, 'Ref::Util::XS' will be installed and used automatically, providing a significant speed boost to everything that uses 'Ref::Util'.

See Ref::Util for full documentation of the available functions.