Re: GdkEventMask?

[Tristan Van Berkom <vantr touchtunes com>]

Andreas Volz wrote:

> Am Thu, 10 Jul 2003 09:42:08 -0400 schrieb Tristan Van Berkom:
>
>  
>
> > > rootwindow = gdk_window_foreign_new
> > > (gdk_x11_get_default_root_xwindow());
> > >      
> > hmmm, this is in some kind of callback function ?
> >
> > This is just an educated guess but here goes:
> >
> > this:
> >
> >    gdk_x11_get_default_root_xwindow()
> >
> > will probably return an int (XID) reference to an X resource (which is
> > an "x window" in
> > this case).
> >
> > and this:
> >
> >   gdk_window_foreign_new(XID *)
> >
> > _will_ create a new GdkWindow.
> >
> > a  "GdkEventMask" will apply to some flags in the newly created
> > "GdkWindow"; it will affect what events you have filtered out in
> > the "gdk" api; not the "xlib" api.
> >
> > so; you want to create _one_ GdkWindow and only reference it
> > in your callbacks. (you probably had some memory leak also
> > from the continous creation of GdkWindow objects).
> >    
>
> I'm not sure if I understand you right, but my app doesn't create a new
> window. My app react only for a GDK_BUTTON_PRESS_MASK in the root
> window. So it's a add-on for WM's without a root menu. And it works
> great.
>
> But when I start my app with a WM running that graps the
> GDK_BUTTON_PRESS_MASK it crashes with this error. I wish to detect if
> the GDK_BUTTON_PRESS_MASK is yet grapped for the root window and exit my
> app.
>
> I think the way it try to do it should work, but it doesn't. Why?
>
> Perhaps now it's better to understand what I try to do.
>  

In the code that you posted you create a new GdkWindow object:

> rootwindow = gdk_window_foreign_new (gdk_x11_get_default_root_xwindow());

this _NEW_ object refers to an already existant X resource (the root 
window).

now your branchstate here:

> unavailable_events = gdk_window_get_events(rootwindow);

> if ((unavailable_events & GDK_BUTTON_PRESS_MASK) == 
GDK_BUTTON_PRESS_MASK)

will always yield the same result because the event mask is freshly 
initialized in your
_NEW_ GdkWindow.

> But it doesn't work. I go everytime into the else-part. What did I wrong?
Thats why.


Cheers,
                       -Tristan