The Palm OS Category Manager provides the user with a consistent interface to categories on the handheld. All applications that use the Category Manager must set aside some space at the beginning of their database's AppInfo block, to be used to store category names and other related information. As a result, the AppBlock objects associated with such an application have a standard set of fields (in addition to any application-specific ones they may also have):
The category names corresponding to the category numbers appearing in the database. Category zero is used to refer to an uncategorized record; its name is always "Unfiled" (or the local language equivalent). The rest of the names are editable by the handheld user.
If a category's entry in this list is true, the category has been renamed by the user since the last synchronization.
Each entry in this list is a unique integer referring to a particular category name. When a new category is created or an existing category is renamed (?) it is given a new ID.
The last integer ID used by the Category Manager; used in generating a new, not previously used ID.