diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 811acb965..873e11986 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,8 @@
+2005-03-04  Pierre Humblet <pierre.humblet@ieee.org>
+
+	* fhandler_socket.cc (fhandler_socket::ioctl): Only cancel
+	WSAAsyncSelect when async mode is on.
+
 2005-03-03  Corinna Vinschen  <corinna@vinschen.de>
 
 	* cygwin.din (utmpxname): Export.
diff --git a/winsup/cygwin/fhandler_socket.cc b/winsup/cygwin/fhandler_socket.cc
index ee93ff517..b7983a1f4 100644
--- a/winsup/cygwin/fhandler_socket.cc
+++ b/winsup/cygwin/fhandler_socket.cc
@@ -1594,7 +1594,7 @@ fhandler_socket::ioctl (unsigned int cmd, void *p)
       /* We must cancel WSAAsyncSelect (if any) before setting socket to
        * blocking mode
        */
-      if (cmd == FIONBIO && *(int *) p == 0)
+      if (cmd == FIONBIO && async_io () && *(int *) p == 0)
 	WSAAsyncSelect (get_socket (), winmsg, 0, 0);
       res = ioctlsocket (get_socket (), cmd, (unsigned long *) p);
       if (res == SOCKET_ERROR)