diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index c9696593d..e12bd85c9 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,7 @@
+2009-07-21  Eric Blake  <ebb9@byu.net>
+
+	* dtable.cc (dup2): Correct return value for no-op.
+
 2009-07-21  Corinna Vinschen  <corinna@vinschen.de>
 	    Eric Blake  <ebb9@byu.net>
 
diff --git a/winsup/cygwin/dtable.cc b/winsup/cygwin/dtable.cc
index 22303dfde..c361d01da 100644
--- a/winsup/cygwin/dtable.cc
+++ b/winsup/cygwin/dtable.cc
@@ -621,7 +621,7 @@ dtable::dup2 (int oldfd, int newfd)
 
   if (newfd == oldfd)
     {
-      res = 0;
+      res = newfd;
       goto done;
     }