CLucene is a C++ port of Lucene: the high-performance, full-featured text search engine written in Java. CLucene is faster than lucene as it is written in C++.
Omseek has been renamed to Xapian. Xapian is a Search Engine Library, written in C++ with bindings for Perl, Python, PHP, Java, Tcl, C# and Ruby. It allows you to easily add advanced indexing and search facilities to your applications.