Subject: bug#9948: valgrind warning: Conditional jump or move depends on uninitialised value(s) in redisplay_window

From: Eli Zaretskii <[email-masked]>
Date: Mon, 07 Nov 2011 01:30:50 -0500

> Date: Sun, 06 Nov 2011 22:08:54 -0800
> From: Paul Eggert <[email-masked]>
> CC: [email-masked]
> 
>   SET_TEXT_POS_FROM_MARKER (startp, w->start);
> 
> does not set startp to a valid charpos if w->start
> points to uninitialized data.

w->startp is the window-start of the window represented by `w'.  It is
a very important player in displaying the window.  If that is
uninitialized, we have a much larger catastrophe on our hands than
some obscure local variable that _could_ be uninitialized ;-)

IOW, if w->startp does not have a valid value, Emacs will crash
pronto.