Index: cygwin/fhandler_serial.cc
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/fhandler_serial.cc,v
retrieving revision 1.40
diff -u -p -r1.40 fhandler_serial.cc
--- cygwin/fhandler_serial.cc	10 Jan 2003 12:32:46 -0000	1.40
+++ cygwin/fhandler_serial.cc	17 Jan 2003 06:37:03 -0000
@@ -725,8 +725,13 @@ fhandler_serial::tcsetattr (int action, 
 
   state.fAbortOnError = TRUE;
 
-  if (memcmp (&ostate, &state, sizeof (state)) != 0)
-    SetCommState (get_handle (), &state);
+  if ((memcmp (&ostate, &state, sizeof (state)) != 0) &&
+      !SetCommState (get_handle (), &state))
+    {
+      /* SetCommState() failed, invalid DCB param (EINVAL in POSIX)*/
+      set_errno (EINVAL);
+      return -1;
+    }
 
   set_r_binary ((t->c_iflag & IGNCR) ? 0 : 1);
   set_w_binary ((t->c_oflag & ONLCR) ? 0 : 1);