External hooks and "link"

[Nick Kew <ni...@webthing.com>]

I have a need to declare and instantiate an optional hook.
it works with APR_DECLARE_EXTERNAL_HOOK and
APR_IMPLEMENT_OPTIONAL_HOOK_RUN_ALL provided I want it
to use RUN_ALL logic (which I do) and return int (which I can
live with, though it's used as void).

The second argument to these macros is called "link" and
looks like a namespacing thing that ties into windows
dllimport/dllexport and simply vanishes on sane platforms.

What would be the purpose of using this?  My context is an
apache module, so presumably I can simply use AP - and
since it only features in macros it won't affect anything
in the object code.  But existing examples like mod_status
do go to all the trouble of defining their own "link"s.

Can anyone explain?

-- 
Nick Kew