Re: make-pointer-invisible on Windows

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 26 Jun 2015 11:15:06 +0200
> From: martin rudalics <rudalics@gmx.at>
> CC: emacs-devel@gnu.org
> 
>  > Btw, how does this work on X?  When we wait in waitpid for a
>  > subprocess launched via "M-!", we are not supposed to call the
>  > read-socket hook, so the X messages that tell us to redraw portions of
>  > our frames are not supposed to be redrawn.
> 
> .. not supposed to be processed.

OK, thanks for confirming my understanding.

> I didn't believe you could (reasonably) redraw the frame while
> waiting for a subprocess, but you somehow sounded optimistic ...

I understand what happens on XP: Windows sens us the WM_PAINT
messages, which the input thread picks up and passes to the main
thread.  But the main thread is busy-waiting inside waitpid, so it
doesn't react to those messages until the subprocess exist.

What I don't understand is how come the frame _is_ redrawn on Windows
7, and that's something I still need to look into.  It might mean
there is a way of keeping the frame display updated after all.  But if
X doesn't, then the motivation for that gets lower, of course.