Richard, I'm also, as you are, a rather inexperienced GTK programmer, but I hope to still help you by the following, without immediately digging into all kinds of technical details : whereever the _swapped variant is used, that is done to call a callback from within a widget, to a procedure that's applicable on another widget (or even, in most cases another widget class).
So e.g., a button press that should be calling some callback procedure on the window it is in, will use the _swapped variant (passing the window pointer as user_data argument). Doing so will make GTK's internal mechanics to "convert/abuse" that user_data argument's value, by putting it into the callback's call as it's *first* argument), so that the window's callback doesn't even realize it used to be the original widget's call's user_data argument). Hope this helps you more than it eventually further confuses you, Kind regards, PhB Richard Riley wrote: >"Matt Hoosier" <[EMAIL PROTECTED]> writes: > > > >>On 11/25/06, Richard <[EMAIL PROTECTED]> 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. >_______________________________________________ >gtk-app-devel-list mailing list >gtk-app-devel-list@gnome.org >http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list > > > > _______________________________________________ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
