bug#16736: Compiling a Lisp file causes display to flash off and on

[Glenn Morris <rgm@gnu.org>]

Eli Zaretskii wrote:

>> In an attempt to follow your instructions, I put a break on dispnew.c:3045.
[...]
> I'm interested in seeing what happens the first time this breakpoint
> breaks after you type "C-x 2" in *scratch*.  (On my system, this is
> the only time it breaks after "C-x 2"; do you see something
> different?)

I do
  gdb> run -Q

and continue a few times until Emacs starts up. If I then select the
Emacs window with the mouse, it breaks twice, so I have to reselect the
gdb window to get it to continue, and then when I select the Emacs
window... Anyway, I can get around that by alt-tabbing back into Emacs.

> Are you saying that tracing into update_window_line and then
> update_text_area for these two, you see that the loop which starts at
> line 3598 ends with i's value smaller than
> desired_row->used[TEXT_AREA], and you see these 3 lines (3696 to 3698)
> being executed:

That does not seem to happen, no.
I have i = stop = 13 = desired_row->used[TEXT_AREA].

> Again, please trace all this upon the first time the breakpoint on
> line 3045 breaks after "C-x 2".