exempi is a port of Adobe XMP SDK to work on UNIX and to be build with 
GNU automake.
It includes XMPCore and XMPFiles, libexempi, a C-based API and exempi a command line tool.

It is maintained by Hubert Figuiere <hub@figuiere.net>

Homepage: http://libopenraw.freedesktop.org/wiki/Exempi