This Notepad++ plugin is simply a front-end to GTags (GNU Global source code tagging system):
http://www.gnu.org/software/global/global.html
It provides tools for easy code navigation.
GTags binaries (Win32 ports) are needed by the plugin. Those are supplied with it for convenience.
This is an extension to GNU Emacs and X-Emacs TAGS functionality, with a
server-side component that narrows down the view of a potentially large TAGS
file and serves the narrowed view over the wire for better performance.
The gTags program brings Microsoft Smart-Tag-like features to Linux in a non-intrusive way. The user can select text from any application, and gTags will pop up a list of actions (such as jumping to a web site) for that text. Tags are configurable via a