defadvice is an autoloaded Lisp macro in `advice.el'.

(defadvice FUNCTION ARGS &rest BODY)

Define a piece of advice for FUNCTION (a symbol).
The syntax of `defadvice' is as follows:


FUNCTION ::= Name of the function to be advised.
CLASS ::= `before' | `around' | `after' | `activation' | `deactivation'.
NAME ::= Non-nil symbol that names this piece of advice.
POSITION ::= `first' | `last' | NUMBER. Optional, defaults to `first',
see also `ad-add-advice'.
ARGLIST ::= An optional argument list to be used for the advised function
instead of the argument list of the original. The first one found in
before/around/after-advices will be used.
FLAG ::= `protect'|`disable'|`activate'|`compile'|`preactivate'.
All flags can be specified with unambiguous initial substrings.
DOCSTRING ::= Optional documentation for this piece of advice.
INTERACTIVE-FORM ::= Optional interactive form to be used for the advised
function. The first one found in before/around/after-advices will be used.
BODY ::= Any s-expression.

Semantics of the various flags:
`protect': The piece of advice will be protected against non-local exits in
any code that precedes it. If any around-advice of a function is protected
then automatically all around-advices will be protected (the complete onion).

`activate': All advice of FUNCTION will be activated immediately if
FUNCTION has been properly defined prior to this application of `defadvice'.

`compile': In conjunction with `activate' specifies that the resulting
advised function should be compiled.

`disable': The defined advice will be disabled, hence, it will not be used
during activation until somebody enables it.

`preactivate': Preactivates the advised FUNCTION at macro-expansion/compile
time. This generates a compiled advised definition according to the current
advice state that will be used during activation if appropriate. Only use
this if the `defadvice' gets actually compiled.