Need in-memory search-tree

[Kevin O'Gorman]

I'm programming a tool in C that needs to keep a really fast database
in memory.  The most likely candidates are red-black or AVL trees.
Deletion need not be supported, so long as the whole thing can be
discarded to reclaim the memory. I could write it, but I'd rather not.

Does anybody have a recommendation for a library that could help me
with this?  Or failing that, a better place to ask?

--
Kevin O'Gorman

programmer, n. an organism that transmutes caffeine into software.