From b5316c68ddc4ebd010928a1b5ae99a32864a8de8 Mon Sep 17 00:00:00 2001
From: "Taylor R. Campbell" <net/mumble/campbell>
Date: Fri, 2 May 2008 03:20:36 +0000
Subject: [PATCH] Change mode in BIND-MODE only if the port is still open.

---
 v7/src/runtime/port.scm | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/v7/src/runtime/port.scm b/v7/src/runtime/port.scm
index d70779750..0b1c7e4ee 100644
--- a/v7/src/runtime/port.scm
+++ b/v7/src/runtime/port.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Id: port.scm,v 1.53 2008/02/02 01:19:10 cph Exp $
+$Id: port.scm,v 1.54 2008/05/02 03:20:36 riastradh Exp $
 
 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
     1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
@@ -885,12 +885,16 @@ USA.
     (if (and read-mode write-mode (read-mode port))
 	(let ((outside-mode))
 	  (dynamic-wind (lambda ()
-			  (set! outside-mode (read-mode port))
-			  (write-mode port mode))
+			  (if (port/open? port)
+			      (begin
+				(set! outside-mode (read-mode port))
+				(write-mode port mode))))
 			thunk
 			(lambda ()
-			  (set! mode (read-mode port))
-			  (write-mode port outside-mode))))
+			  (if (port/open? port)
+			      (begin
+				(set! mode (read-mode port))
+				(write-mode port outside-mode))))))
 	(thunk))))
 
 ;;;; Standard Ports
-- 
2.25.1