#include <gtk/gtk.h>
#include <stdio.h>

void callback (char *data, void *p, void *p2) {
   printf ("Callback being called: data = %p (%s)\n", data, data);
   printf ("                       p    = %p\n", p);
   printf ("                       p2   = %p\n", p2);
   printf ("   p  is object? %d\n", G_IS_OBJECT (p));
   printf ("   p2 is object? %d\n", G_IS_OBJECT (p2));
   gtk_main_quit();
}

void callback2 (char *data, GtkWidget *p) {
   printf ("Callback being called: data = %p (%s)\n", data, data);
   printf ("                       ptr  = %p\n", p);
   printf ("   is object? %d\n", G_IS_OBJECT (p));
}

int main (int argc, char **argv) {
    GtkWidget *w, *b;
    GClosure *c, *c2;
    char *data = "Some data";

    printf ("data = %p\n", data);
    /* Init and create new window */ 
    gtk_init (&argc, &argv);
    w = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    b = gtk_button_new_with_label ("A quite long title for a button");
    gtk_container_add (GTK_CONTAINER(w), b);
    gtk_widget_show_all (w);
    printf ("window = %p\n", w);
    printf ("button = %p\n", b);
    
    /* Create closures and connect */
    c = g_cclosure_new_swap (G_CALLBACK(callback), data, NULL);
    g_signal_connect_closure (w, "delete-event", c, 0);
    c2 = g_cclosure_new_swap (G_CALLBACK(callback2), data, NULL);
    g_signal_connect_closure (b, "clicked", c2, 0);
    
    gtk_main ();
    return 0;
}