Component Types for Clocks(IM: QC)

Inside Macintosh: QuickTime Components /: Chapter 11 - Clock Components / Clock Components Reference

Component Types for Clocks
Apple has defined a type value and a number of subtype values for clock components. All clock components have a component type value of 'clok'. The component subtype value indicates the type of clock. You can use the following constants to specify these type and subtype values.
#define clockComponentType        'clok'  /* clock component type */
#define systemTickClock           'tick'  /* system tick clock */
#define systemSecondClock         'seco'  /* system seconds clock */
#define systemMillisecondClock    'mill'  /* system millisecond clock */
#define systemMicrosecondClock    'micr'  /* system microsecond clock */