Redland RDF Application Framework
- http://librdf.org/
- Set of RDF libraries in C: Core, Syntax, Query
- High performance: small, fast, low memory use
- Mature and stable: 5 years of development, shipped with Linuxes
- Portable: POSIX, Unix, Linux, OSX, Win32
- Bindings to C#, Perl, Python, Ruby, PHP, ObjC
(Tcl, Java)