Legacy Document

Important: The information in this document is obsolete and should not be used for new development.

Inside Macintosh: Macintosh Toolbox Essentials /: Chapter 3 - Menu Manager / About the Menu Manager

How the Menu Manager Maintains Information About Menus
The Menu Manager maintains information about menus in menu records. Each menu record includes certain information about a specific menu, including

the menu ID of the menu
the horizontal and vertical dimensions of the menu (in pixels)
a handle to the menu definition procedure of the menu
flags indicating whether each item (for the first 31 items) is enabled or disabled and whether the menu title is enabled or disabled
the contents of the menu, including the menu title and other data that defines the menu items

You typically specify most of this information in a menu resource, that is, a resource of type 'MENU'. When you create a menu, the Menu Manager stores this information in a menu record. A menu record is a data structure of type MenuInfo. You usually never need to access the information in the menu record directly; the Menu Manager automatically updates the menu record when you make any changes to the menu, such as adding a menu item. See "The Menu Record" beginning on page 3-97 if you need to access the fields of the menu record directly.
The Menu Manager identifies every menu by a number referred to as a menu ID. You must assign a menu ID to each menu in your application. Each menu in your application must have a menu ID that is unique from that of any other menu in your application. You can use any number greater than 0 for a menu ID of a pull-down or pop-up menu; submenus of an application can use only menu IDs from 1 through 235; submenus of a desk accessory must use menu IDs from 236 through 255.
When you create a menu, the Menu Manager creates a menu record for the menu and returns a handle to that menu record. To refer to a menu, you usually use either the menu's menu ID or a handle to the menu's menu record.
To refer to a menu item, use the menu item's item number. Item numbers identify items in menus; items are assigned item numbers starting with 1 for the first menu item in the menu, 2 for the second menu item in the menu, and so on, up to the number of the last menu item in the menu.