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

static GtkWidget *combo1;
static GtkWidget *combo2;

static GList *one_list;
static GList *two_list;
static GList *three_list;

void
callback (GtkEntry *entry)
{
    if (strcmp ("one", gtk_entry_get_text (entry)) == 0)
	gtk_combo_set_popdown_strings (GTK_COMBO (combo2), one_list);
    else if (strcmp ("two", gtk_entry_get_text (entry)) == 0)
	gtk_combo_set_popdown_strings (GTK_COMBO (combo2), two_list);
    else if (strcmp ("three", gtk_entry_get_text (entry)) == 0)
	gtk_combo_set_popdown_strings (GTK_COMBO (combo2), three_list);
    else
	; // no list for this one
}

int
main (int argc, char *argv[])
{
    GtkWidget *win;
    GtkWidget *vbox;
    GList *popdown_list;

    gtk_init (&argc, &argv);

    win = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    vbox = gtk_vbox_new (TRUE, 0);
    gtk_container_add (GTK_CONTAINER (win), vbox);

    combo1 = gtk_combo_new ();
    gtk_box_pack_start (GTK_BOX (vbox), combo1, FALSE, FALSE, 0);

    popdown_list = NULL;
    popdown_list = g_list_prepend (popdown_list, "three");
    popdown_list = g_list_prepend (popdown_list, "two");
    popdown_list = g_list_prepend (popdown_list, "one");

    gtk_combo_set_popdown_strings (GTK_COMBO (combo1), popdown_list);
    gtk_signal_connect (GTK_OBJECT (GTK_COMBO (combo1)->entry),
			"changed",
			GTK_SIGNAL_FUNC (callback),
			NULL);

    combo2 = gtk_combo_new ();
    gtk_box_pack_start (GTK_BOX (vbox), combo2, FALSE, FALSE, 0);

    one_list = NULL;
    one_list = g_list_prepend (one_list, "nsa");
    one_list = g_list_prepend (one_list, "fbi");
    one_list = g_list_prepend (one_list, "cia");

    two_list = NULL;
    two_list = g_list_prepend (two_list, "justice");
    two_list = g_list_prepend (two_list, "infinite");

    three_list = NULL;
    three_list = g_list_prepend (three_list, "pgp");
    three_list = g_list_prepend (three_list, "gpg");
    three_list = g_list_prepend (three_list, "rsa");

    gtk_combo_set_popdown_strings (GTK_COMBO (combo2), one_list);

    gtk_widget_show_all (win);

    gtk_main ();

    return 0;
}