GNU Emacs functions can be extended by advising them. Use this tag for questions that are directly related to advising Emacs functions.
There are two advice systems for GNU Emacs:
- The traditional system, which uses Emacs Lisp macro
defadviceto advise a function. - The new system, which uses macros
add-functionandremove-function, and which is implemented in librarynadvice.el.
The Elisp manual, node Advising Functions, provides the documentation for this topic.