(message_cleared_p): New variable.

(clear_message): Set message_cleared_p when clearing the current
message.
(redisplay_internal): Look at message_cleared_p to capture
the case that the echo area should be cleared.

2 files changed, 24 insertions, 3 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 0fa5c980ad1..50ecb0f7ccb 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,11 @@
 2001-08-01  Gerd Moellmann  <gerd@gnu.org>
 
+        * xdisp.c (message_cleared_p): New variable.
+        (clear_message): Set message_cleared_p when clearing the current
+        message.
+        (redisplay_internal): Look at message_cleared_p to capture
+        the case that the echo area should be cleared.
+
         * keyboard.c (command_loop_1): Fix spelling of
         resize_echo_area_exactly.
 
diff --git a/src/xdisp.c b/src/xdisp.c
index 91b2a5e8a6d..7e0a9eea5e4 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -510,6 +510,11 @@ Lisp_Object Vmax_mini_window_height;
 int message_truncate_lines;
 Lisp_Object Qmessage_truncate_lines;
 
+/* Set to 1 in clear_message to make redisplay_internal aware
+   of an emptied echo area.   */
+
+static int message_cleared_p;
+
 /* Non-zero means we want a hollow cursor in windows that are not
    selected.  Zero means there's no cursor in such windows.  */
 
@@ -6895,7 +6900,10 @@ clear_message (current_p, last_displayed_p)
      int current_p, last_displayed_p;
 {
   if (current_p)
-    echo_area_buffer[0] = Qnil;
+    {
+      echo_area_buffer[0] = Qnil;
+      message_cleared_p = 1;
+    }
   
   if (last_displayed_p)
     echo_area_buffer[1] = Qnil;
@@ -8406,12 +8414,19 @@ redisplay_internal (preserve_echo_area)
   /* Normally the message* functions will have already displayed and
      updated the echo area, but the frame may have been trashed, or
      the update may have been preempted, so display the echo area
-     again here.  Checking both message buffers captures the case that
+     again here.  Checking message_cleared_p captures the case that
      the echo area should be cleared.  */
-  if (!NILP (echo_area_buffer[0]) || !NILP (echo_area_buffer[1]))
+  if (!NILP (echo_area_buffer[0]) || message_cleared_p)
     {
       int window_height_changed_p = echo_area_display (0);
       must_finish = 1;
+
+      /* If we don't display the current message, don't clear the
+         message_cleared_p flag, because, if we did, we wouldn't clear
+         the echo area in the next redisplay which doesn't preserve
+         the echo area.  */
+      if (!display_last_displayed_message_p)
+        message_cleared_p = 0;
       
       if (fonts_changed_p)
         goto retry;