Inside Macintosh: Macintosh Toolbox Essentials
This section describes the enumerators and types for event kinds, event masks, event modifier flags, and posting options; the event record structure, target ID structure, high-level event message structure, and structure of the Operating System event queue; and the filter function types and macros.
The Event Manager uses event records to return information about events. You can use a target ID structure to specify or identify the address of another application or process with which your application is communicating. If your application supplies a filter function as a parameter to the GetSpecificHighLevelEvent function, your filter function receives information about high-level events in a high-level event message structure.