Hi Seeing this discussion I have a doubt.
What does this gpointer data in the function arguments mean. How I can use it and in what all contexts. > void callback (GtkButton *button, > gpointer data); Thanks Dino Sven Neumann wrote: > > Hi, > > Shiraz Baig <[EMAIL PROTECTED]> writes: > > > I am a newbie. Can anyone tell me, in the following > > elementary program, why doesn't the function "hello" > > that it has not been passed any data. Because in > > gtk-signal-connect, we are passing NULL data. > > Wherefrom is this data coming. In another case, I have > > seen drawing_area being passed like this. How does it > > get to the function "hello". > > what was the question again? The code you posted looks > OK and I can't see what your question is. data as passed > to the function hello should indeed be NULL. > > If you have seen a drawing_area pointer in a signal > callback where you expected your user_data you most > probably connected a callback with a wrong signature. > Not all signals are declared as the clicked signal > of a GtkButton: > > void (* clicked) (GtkButton *button); > > which expects a callback of the form > > void callback (GtkButton *button, > gpointer data); > > The signal "expose_event" of a GtkWidget for > example is defined as > > gint (* expose_event) (GtkWidget *widget, > GdkEventExpose *event); > > so you need to use a callback of the form > > gint callback (GtkWidget *widget, > GdkEventExpose *event, > gpointer data); > > Or you'd get the event pointer instead of the expected > user_data. > > Salut, Sven > _______________________________________________ > gtk-list mailing list > [EMAIL PROTECTED] > http://mail.gnome.org/mailman/listinfo/gtk-list _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com _______________________________________________ gtk-list mailing list [EMAIL PROTECTED] http://mail.gnome.org/mailman/listinfo/gtk-list
