Clarify that SETFUNCTION is only used in the Customize user interface

(bug#6089).

doc/lispref/ChangeLog

 2011-07-02  Lars Magne Ingebrigtsen  <larsi@gnus.org>
 
+	* customize.texi (Variable Definitions): Clarify that SETFUNCTION
+	is only used in the Customize user interface (bug#6089).
+
 	* display.texi (Showing Images): Mention the point of sliced
 	images (bug#7836).
 

doc/lispref/customize.texi

@@ -326,11 +326,12 @@ individual types for a description of how to use @code{:options}.
 @item :set @var{setfunction}
 @kindex set@r{, @code{defcustom} keyword}
 Specify @var{setfunction} as the way to change the value of this
-option.  The function @var{setfunction} should take two arguments, a
-symbol (the option name) and the new value, and should do whatever is
-necessary to update the value properly for this option (which may not
-mean simply setting the option as a Lisp variable).  The default for
-@var{setfunction} is @code{set-default}.
+option when using the Customize user interface.  The function
+@var{setfunction} should take two arguments, a symbol (the option
+name) and the new value, and should do whatever is necessary to update
+the value properly for this option (which may not mean simply setting
+the option as a Lisp variable).  The default for @var{setfunction} is
+@code{set-default}.
 
 @item :get @var{getfunction}
 @kindex get@r{, @code{defcustom} keyword}

lisp/ChangeLog

 2011-07-02  Lars Magne Ingebrigtsen  <larsi@gnus.org>
 
+	* custom.el (defcustom): Clarify that :set is only used in the
+	Customize user interface (bug#6089).
+
 	* progmodes/flymake.el (flymake-mode): If the buffer isn't
 	associated with a file, refuse to run instead of erroring out
 	(bug#6084).

lisp/custom.el

@@ -215,7 +215,8 @@ The following keywords are meaningful:
 	variable.  It takes two arguments, the symbol and value
 	given in the `defcustom' call.  The default is
 	`custom-initialize-reset'.
-:set	VALUE should be a function to set the value of the symbol.
+:set	VALUE should be a function to set the value of the symbol
+        when using the Customize user interface.
 	It takes two arguments, the symbol to set and the value to
 	give it.  The default choice of function is `set-default'.
 :get	VALUE should be a function to extract the value of symbol.