Re: invalid unclassed pointer?

    Vlad> It should be: gboolean draw_histogram (GtkWidget *widget,
    Vlad> GdkEventExpose *event, gpointer user_data); i.e. it should accept 3
    Vlad> params instead of two.

Like one pair of functions (basically) to set/get values on an object, this is
another area where Xt was designed correctly IMHO.  In Xt, all callbacks have
the same 4 parameters.  In GTK terms the prototype would be:

  void (*callback)(GtkWidget *widget, GdkEvent *event,
                   gpointer call_data, gpointer client_data);

While coding, I find it convenient to have exactly the parameters I need for
callbacks, but I have a hard time remembering the parameters required for the
different callbacks.  Even in my own widgets.
Mark Leisher
Computing Research Lab            Once you fully apprehend the vacuity of a
New Mexico State University       life without struggle, you are equipped
Box 30001, Dept. 3CRL             with the basic means of salvation.
Las Cruces, NM  88003                            -- Tennessee Williams

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