X-Git-Url: http://ncurses.scripts.mit.edu/?p=ncurses.git;a=blobdiff_plain;f=ncurses%2Ftty%2Ftty_update.c;h=866681369a108ab989a3b45ce3e4dea84ddb7bbd;hp=33c79c7c0d5118d6c756abefe562a4a25e30c72a;hb=491a3f08b795f494ae17179338c31a11b18fd433;hpb=28e9f9700c7bf7280cf9d71304a880b570a0b4ea

diff --git a/ncurses/tty/tty_update.c b/ncurses/tty/tty_update.c
index 33c79c7c..86668136 100644
--- a/ncurses/tty/tty_update.c
+++ b/ncurses/tty/tty_update.c
@@ -74,7 +74,7 @@
 #include <ctype.h>
 #include <term.h>
 
-MODULE_ID("$Id: tty_update.c,v 1.242 2007/09/29 20:37:13 tom Exp $")
+MODULE_ID("$Id: tty_update.c,v 1.243 2007/10/13 20:03:32 tom Exp $")
 
 /*
  * This define controls the line-breakout optimization.  Every once in a
@@ -624,6 +624,10 @@ doupdate(void)
 
     T((T_CALLED("doupdate()")));
 
+    if (curscr == 0
+	|| newscr == 0)
+	returnCode(ERR);
+
 #ifdef TRACE
     if (USE_TRACEF(TRACE_UPDATE)) {
 	if (curscr->_clear)