Re: Possible fix for crash in NS's tooltip showAtX:Y:for:

[YAMAMOTO Mitsuharu]

>>>>> On Mon, 29 Apr 2013 13:56:49 -0400, David Reitter <address@hidden> said:

> Suggest to initialize ns_tooltip as shown below.  I've been seeing
> occasional crash reports in Fx_show_tip (and showAtX).  This may be
> the culprit.  (I am not sure if variables in ObjC default to nil all
> the time.)

> --- a/src/nsfns.m
> +++ b/src/nsfns.m
> @@ -88,7 +88,7 @@ Lisp_Object Qfontsize;
>  /* hack for OS X file panels */
>  char panelOK = 0;
 
> -EmacsTooltip *ns_tooltip;
> +EmacsTooltip *ns_tooltip = nil;
 
Objective C is not different from the usual C in this respect (i.e.,
implicit initialization of objects that have static storage duration).
So the above change does not give any effect in theory, because `nil'
is actually a null pointer.

But in practice, it can affect the arrangement of locations of
variables in the executable file.  If this change really avoids a
crash in Fx_show_tip, then that might be a sign of some memory
corruption such as buffer overrun around the original location of
ns_tooltip, and thus this change might cause another problem.

                                     YAMAMOTO Mitsuharu
                                address@hidden