define-obsolete-variable-alias

define-obsolete-variable-alias is a Lisp macro in `byte-run.el'.

(define-obsolete-variable-alias OBSOLETE-NAME CURRENT-NAME WHEN &optional DOCSTRING)

Make OBSOLETE-NAME a variable alias for CURRENT-NAME and mark it obsolete.
This uses `defvaralias' and `make-obsolete-variable' (which see).
See the Info node `(elisp)Variable Aliases' for more details.

If CURRENT-NAME is a defcustom (more generally, any variable
where OBSOLETE-NAME may be set, e.g. in an init file, before the
alias is defined), then the define-obsolete-variable-alias
statement should be evaluated before the defcustom, if user
customizations are to be respected. The simplest way to achieve
this is to place the alias statement before the defcustom (this
is not necessary for aliases that are autoloaded, or in files
dumped with Emacs). This is so that any user customizations are
applied before the defcustom tries to initialize the
variable (this is due to the way `defvaralias' works).

For the benefit of `custom-set-variables', if OBSOLETE-NAME has
any of the following properties, they are copied to
CURRENT-NAME, if it does not already have them:
'saved-value, 'saved-variable-comment.