5:56 a.m.
In lwlib/lwlib-Xlw.c:xlw_update_one_widget, we have
#ifdef LWLIB_MENUBARS_LUCID
else if (class == xlwMenuWidgetClass)
{
XlwMenuWidget mw;
Arg al [1];
if (XtIsShell (widget))
mw = (XlwMenuWidget)((CompositeWidget)widget)->composite.children [0];
else
mw = (XlwMenuWidget)widget;
XtSetArg (al [0], XtNmenu, val);
XtSetValues (widget, al, 1);
}
#endif
Note how the code carefully creates a mw widget, and then ignores it.
Perhaps the XtSetValues call should be
XtSetValues (mw, al, 1);
8:32 a.m.
I didn't write this code and I don't understand it :)
andy
At 02:56 PM 11/18/00 +0900, Martin Buchholz wrote:
In lwlib/lwlib-Xlw.c:xlw_update_one_widget, we have
#ifdef LWLIB_MENUBARS_LUCID
else if (class == xlwMenuWidgetClass)
{
XlwMenuWidget mw;
Arg al [1];
if (XtIsShell (widget))
mw = (XlwMenuWidget)((CompositeWidget)widget)->composite.children
[0];
else
mw = (XlwMenuWidget)widget;
XtSetArg (al [0], XtNmenu, val);
XtSetValues (widget, al, 1);
}
#endif
Note how the code carefully creates a mw widget, and then ignores it.
Perhaps the XtSetValues call should be
XtSetValues (mw, al, 1);
--------------------------------------------------------------
Dr Andy Piper
Principal Consultant, BEA Systems Ltd
9:55 a.m.
Andy Piper <andyp(a)bea.com> wrote:
I didn't write this code and I don't understand it :)
andy
At 02:56 PM 11/18/00 +0900, Martin Buchholz wrote:
>In lwlib/lwlib-Xlw.c:xlw_update_one_widget, we have
>
>#ifdef LWLIB_MENUBARS_LUCID
> else if (class == xlwMenuWidgetClass)
> {
> XlwMenuWidget mw;
> Arg al [1];
> if (XtIsShell (widget))
> mw = (XlwMenuWidget)((CompositeWidget)widget)->composite.children
> [0];
> else
> mw = (XlwMenuWidget)widget;
> XtSetArg (al [0], XtNmenu, val);
> XtSetValues (widget, al, 1);
> }
>#endif
>
>
>Note how the code carefully creates a mw widget, and then ignores it.
>
>Perhaps the XtSetValues call should be
>
>XtSetValues (mw, al, 1);
I think you're right. Under X, all Xt derived widgets that create X
windows outside the main application's window tree (this is the case for
menus, dialogs and the like) are actually wrapped in Shell widgets. Some
toolkits (Motif for instance) make this transparent to the programmer[1]. I
think that this code just tries to find the real widget concerned by the
update.
Footnotes:
[1] This has nasty drawbacks. Functions like XmCreate*Dialog return the
real dialog widget, not the shell in which it is wrapped. This leads to nasty
bugs when novice programmers try to work on the shell while believing they
already know it.
--
/ / _ _ Didier Verna http://www.inf.enst.fr/~verna/
- / / - / / /_/ / EPITA / LRDE mailto:didier＠lrde.epita.fr
/_/ / /_/ / /__ / 14-16 rue Voltaire Tel. +33 (1) 53 14 59 47
94276 Kremlin-Bicêtre cedex Fax. +33 (1) 44 08 01 99
5:15 a.m.
>>>> "drv" == Didier Verna
<didier(a)xemacs.org> writes:
> >Note how the code carefully creates a mw widget, and then
ignores it.
> >
> >Perhaps the XtSetValues call should be
> >
> >XtSetValues (mw, al, 1);
drv> I think you're right. Under X, all Xt derived widgets that create X
drv> windows outside the main application's window tree (this is the case for
drv> menus, dialogs and the like) are actually wrapped in Shell widgets. Some
drv> toolkits (Motif for instance) make this transparent to the programmer[1]. I
drv> think that this code just tries to find the real widget concerned by the
drv> update.
I don't understand the code, so I'm inclined not to change it without
proving there's a bug there. Project for Didier or some other
Xt-aware hacker?
Martin
5:44 a.m.
>>>> "mb" == Martin Buchholz
<martin(a)xemacs.org> writes:
drv> think that this code just tries to find the real widget
drv> concerned by the update.
mb> I don't understand the code, so I'm inclined not to change it
mb> without proving there's a bug there. Project for Didier or
mb> some other Xt-aware hacker?
I'm not that, but I'm willing to experiment. Didier's explanation is
plausible; there is one other example of similar code, also using the
mw temporary variable, and it _does_ do the XSetValues on mw. I'll do
s/widget/mw/ here. (All the other uses of XtIsShell in lwlib and src
actually chase the chain of parents for some reason.)
If anybody has suggestions for experiments or anomolies I should look for?
--
University of Tsukuba Tennodai 1-1-1 Tsukuba 305-8573 JAPAN
Institute of Policy and Planning Sciences Tel/fax: +81 (298) 53-5091
_________________ _________________ _________________ _________________
What are those straight lines for? "XEmacs rules."
8767
days inactive
8770
days old
4 comments
4 participants
participants (4)
-
Andy Piper -
Didier Verna -
Martin Buchholz -
Stephen J. Turnbull