CtagsInterface provides source code tagging functionality using the "Exuberant Ctags" tool (http://ctags.sourceforge.net). It automatically invokes Ctags on a list of projects (or source code trees) and keeps the tag information in a database. Outstanding functionalities:

In addition, CtagsInterface provides a convenient API to access the tag index, so that the tag information can be shared with other plugins as well, and to eliminate the need for other plugins to interface with Ctags directly.

CtagsInterface is highly-configurable and can make use of all the information provided by Ctags. All tag extensions are indexed and made available to other plugins by the API.