Combo listbox signal capture

[author <millward Ms UManitoba CA>]

How do I capture the signal when any item in a list is selected?
This list is part of a combo box.
I understand that that for a single item you do something like this:
  GtkWidget  * item;
  item = CreateItem( item's name );
  gtk_signal_connect(GTK_OBJECT(item), "select",
      GTK_SIGNAL_FUNC( callback ),  whateverdata );
 And the callback is something like:
void  callback(GtkWidget * widget, gpointer * data )
{
  do whatever
}
  Ok. That's fine for a SINGLE item. But what about if you want
ANY item in the list to activate a callback?
What if you have 50 items in lthe list? Do you have to use
CreateItem() for each and every one of them?
     For example, my combo box has a list of 5 items. How
do I get any one of them, when clicked, to  activate the
same callback? 
And what signal do I catch for a button click on an item
in a list?  "select"  I assume. Y/N?
This is my code so far, but off course, it doesn't quite
work yet.
 
#include <stdio.h>  /* printf() */
#include <gtk/gtk.h>

typedef struct cdata
{
  GtkWidget * combo;   
  GtkWidget * label;
  GList * cbitems;
} CData;

/*    For GtkItemClass
   void ( * select ) (GtkItem * item );  */
static void  item_selected(GtkItem * item,  CData * data)
{
   g_print("\n Item selected was  %s \n",  data.cbitems );
}

statc void GetComboEntry(GtkWidget * widget,
                                                   CData * data)
{    
  char * val = (char *) NULL;
  
  val = gtk_entry_get_text(
   GTK_ENTRY(GTK_COMBO(data->combo)->entry) );

 if( val )
 {
    printf("\nValue selected is %s\n", val);
    gtk_label_set_text(GTK_LABEL(data->label), val); 
 }
} /* end of function GetComboEntry */

int main( int argc, char * argv[] )
{
  GtkWidget * window, * button, * vbox;
  GtkEntry * entry;
  GtkWidget * list;  
 
  CData data;
  
  data.cbitems = NULL;
  gtk_init(&argc, &argv);  

  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);

  gtk_signal_connect(GTK_OBJECT(window), "delete_event",
                     GTK_SIGNAL_FUNC(gtk_main_quit),
                     NULL );

  vbox = gtk_vbox_new(FALSE, 0);

  gtk_window_position(GTK_WINDOW(window),
                      GTK_WIN_POS_MOUSE);
  
  data.combo = gtk_combo_new();
  data.cbitems = g_list_append(data.cbitems, "Yesterday");    
  data.cbitems = g_list_append(data.cbitems, "Today");
  data.cbitems = g_list_append(data.cbitems, "Tomorrow");
  data.cbitems = g_list_append(data.cbitems, "Today + 2");
  data.cbitems = g_list_append(data.cbitems, "Today + 3");
  data.cbitems = g_list_append(data.cbitems, "Today + 4");
  
  gtk_combo_set_popdown_strings(GTK_COMBO(data.combo),
                                                               data.cbitems );

  gtk_container_add(GTK_CONTAINER(vbox), data.combo ); 

/* Entry box NOT editable */
  entry = GTK_ENTRY(GTK_COMBO(data.combo)->entry);
  gtk_entry_set_editable(entry, FALSE);                                       

  gtk_signal_connect(GTK_ITEM(data.combo), "select",
              GTK_SIGNAL_FUNC(item_selected), &data );

  button = gtk_button_new_with_label("OK");
  gtk_signal_connect(GTK_OBJECT(button), "clicked",
                     GTK_SIGNAL_FUNC(GetComboEntry ), &data);

  data.label = gtk_label_new("Date/Year");
  gtk_container_add(GTK_CONTAINER(vbox), data.label);
  gtk_container_add(GTK_CONTAINER(vbox), button );
  gtk_container_add(GTK_CONTAINER(window), vbox);
  gtk_widget_show_all(window);

  gtk_main();

  return 0;
} /* end of program combo_1.c  Logan GTK page 777 */