passing data to Menu handler function

[Carlos Pereira <carlos pehoe civil ist utl pt>]

Dear all,
Typically, the event_handler to pop up a menu looks like this:

static gint button_press_handler (GtkWidget *widget, GdkEvent *event)
{ .
  gtk_menu_popup (menu, ...
  .
}

Now the question is, how can I pass data to this function (not talking of
external variables of course)? When I try a function with three arguments
static gint button_press (GtkWidget *widget, GdkEvent *event, gpointer data)
I always get errors. In fact, all the examples I see use a signal_connect_object 
function, where the object is the menu, which makes it difficult to pass a gpointer...

Thanks for the help!

Carlos