[xml] DTD location help

[<tlewis mindspring com>]

I am packaging my application up for release & distribution, and I am
struggling with how to handle my DTDs.  Different *nix distributions have
different policies on where DTDs and other system components should go,
and so I am hesitant to specify the location as an absolute "file://"
path.  Rather, I would like to state the DTD and have it be discovered
under to the local file arrangement.

If I am not mistaken, this is the purpose of catalogs.  I've never used
a catalog, I am unclear on the differences between SGML and XML catalogs,
and I am unfamiliar with the libxml interfaces for handling these issues.
Could anyone point me to some documentation or example code, or provide
some tips, that could clarify this issue for me?  I don't need a catalog
primer as much as I need info/examples on the libxml-specific portions,
but anything would be appreciated.

If this is too noisy for the list, then please feel free to reply
privately to me.  TIA.

--
Todd Lewis
tlewis mindspring com