Re: g_signal_connect_swapped

[Richard Riley <rileyrg googlemail com>]

"Matt Hoosier" <matt hoosier gmail com> writes:

> On 11/25/06, Richard <rileyrg googlemail com> wrote:
> > Could someone explain the reason for this function
> >
> > "g_signal_connect_swapped"
> >
> > I have read the manual here:
> >
> > http://www.gtk.org/tutorial/x159.html
> >
> > where it says:
> >
> > ,----
> > | g_signal_connect_swapped() is the same as g_signal_connect() except that
> > | the instance on which the signal is emitted and data will be swapped
> > | when calling the handler. So when using this function to connect
> > | signals, the callback should be of the form
> > |
> > |
> > | void callback_func( gpointer   callback_data,
> > |                     ... /* other signal arguments */
> > |                     GtkWidget *widget);
> > |
> > | where the object is usually a widget.
> > `----
> >
> > Could anyone express this a little clearer? I (as a gtk beginner) can
> > see no reason for it.
>
> This just means that the "widget" and "callback_data" pointers will be
> pushed onto the call stack in the opposite order from their ordering
> if hooked up with g_signal_connect(). If you're designing your own
> callback function, this probably isn't useful; just use
> g_signal_connnect() with a callback that has GObject* and gpointer
> parameters [in that order].

I can see the order has changed - it was the reason I was looking for. I
don't currently see the point. Maybe it will become clearer as I learn
more.