=== modified file 'lisp/net/rcirc.el'
--- lisp/net/rcirc.el	2011-08-04 00:58:07 +0000
+++ lisp/net/rcirc.el	2011-08-17 13:43:29 +0000
@@ -149,7 +149,9 @@
 maximum frame width."
   :type '(choice (const :tag "Value of `fill-column'")
 		 (const :tag "Full frame width" frame-width)
-		 (integer :tag "Number of columns"))
+		 (const :tag "Full window width" window-width)
+		 (integer :tag "Number of columns")
+		 (function :tag "Return value of function" function))
   :group 'rcirc)
 
 (defcustom rcirc-fill-prefix nil
@@ -2421,13 +2423,16 @@
     (let ((fill-prefix
 	   (or rcirc-fill-prefix
 	       (make-string (- (point) (line-beginning-position)) ?\s)))
-	  (fill-column (- (cond ((eq rcirc-fill-column 'frame-width)
-				 (1- (frame-width)))
-				(rcirc-fill-column
-				 rcirc-fill-column)
-				(t fill-column))
-			  ;; make sure ... doesn't cause line wrapping
-			  3)))
+	  (fill-column
+	   (cond ((eq rcirc-fill-column 'frame-width)
+		  (1- (frame-width)))
+		 ((eq rcirc-fill-column 'window-width)
+		  (1- (window-width)))
+		 ((fboundp rcirc-fill-column) ; custom function
+		  (funcall rcirc-fill-column sender response))
+		 (rcirc-fill-column    	; fix integer value
+		  rcirc-fill-column)
+		 (t fill-column))))
       (fill-region (point) (point-max) nil t))))
 
 ;;; handlers