[prog] ncurses menu code

[ed orphan]

There's a line of code in the Ncurses Programming HOWTO
I need help understanding. It's the last example in
the chapter on menus, example 24, Menu User Pointer Usage.
In the switch,  
   case 10:  /* Enter */
   {    ITEM * cur;     pointer to a menu item declared
        void (*p) (char  * );   pointer declared to a function that
                 returns void and has a char pointer as an argument.
        cur = current_item( my_menu );
                 current_item returns a pointer to the current item in
                 the menu called my_menu.
        p = item_userptr( cur );
                 Assigning the function item_userptr( cur ) to the
                 function pointer p.  ( why I have no idea ).
                 All the man file says about item_userptr is that:
                 "Every menu item has a field that can be used to
                  hold application-specific data". item_userptr 
                  retrieves that field.
        p( ( char *)item_name( cur ) );
                Dah?  What is this?
                I know that item_name returns the name part of the
                the given item and is defined as:
                const char *item_name(const ITEM *item)
                What does this statement do? 
                Is there a simpler, more understandable method to
                get the same job done?
Any information would be very welcome.  Thanks.