(update_frame_1): Check if tty output is still valid before flushing

it.

diff --git a/src/dispnew.c b/src/dispnew.c
index ccfac545753e0a80f4c1c5b20cc23c4f1597d6f5..f61b18de444843f2a50f05cdaa8892b33cf941d7 100644 (file)
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -5302,22 +5302,26 @@ update_frame_1 (f, force_p, inhibit_id_p)
                 Also flush out if likely to have more than 1k buffered
                 otherwise.   I'm told that some telnet connections get
                 really screwed by more than 1k output at once.  */
-             int outq = PENDING_OUTPUT_COUNT (FRAME_TTY (f)->output);
-             if (outq > 900
-                 || (outq > 20 && ((i - 1) % preempt_count == 0)))
+             FILE *display_output = FRAME_TTY (f)->output;
+             if (display_output)
                {
-                 fflush (FRAME_TTY (f)->output);
-                 if (preempt_count == 1)
+                 int outq = PENDING_OUTPUT_COUNT (display_output);
+                 if (outq > 900
+                     || (outq > 20 && ((i - 1) % preempt_count == 0)))
                    {
+                     fflush (display_output);
+                     if (preempt_count == 1)
+                       {
 #ifdef EMACS_OUTQSIZE
-                     if (EMACS_OUTQSIZE (0, &outq) < 0)
-                       /* Probably not a tty.  Ignore the error and reset
-                          the outq count.  */
-                       outq = PENDING_OUTPUT_COUNT (FRAME_TTY (f->output));
+                         if (EMACS_OUTQSIZE (0, &outq) < 0)
+                           /* Probably not a tty.  Ignore the error and reset
+                              the outq count.  */
+                           outq = PENDING_OUTPUT_COUNT (FRAME_TTY (f->output));
 #endif
-                     outq *= 10;
-                     if (baud_rate <= outq && baud_rate > 0)
-                       sleep (outq / baud_rate);
+                         outq *= 10;
+                         if (baud_rate <= outq && baud_rate > 0)
+                           sleep (outq / baud_rate);
+                       }
                    }
                }
            }