Doc string clarification for defcustom

* lisp/custom.el (defcustom): Mention `custom-declare-variable' in
the doc string(bug#22703).

1 files changed, 5 insertions, 0 deletions

diff --git a/lisp/custom.el b/lisp/custom.el
index 736460fec7b..9bd9712b65c 100644
--- a/lisp/custom.el
+++ b/lisp/custom.el
@@ -336,6 +336,11 @@ to load a file defining variables with this form, or with
 _outside_ any bindings for these variables.  (`defvar' and
 `defconst' behave similarly in this respect.)
 
+This macro calls `custom-declare-variable'.  If you want to
+programmatically alter a customizable variable (for instance, to
+write a package that extends the syntax of a variable), you can
+call that functcion directly.
+
 See Info node `(elisp) Customization' in the Emacs Lisp manual
 for more information."
   (declare (doc-string 3) (debug (name body)))