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Provides timers that asynchronously notify an application after an interval or at a specific time.
The User class in the System Static Functions
API provides simple functions to suspend a thread for a given interval or until
a specific time.
The API has three key concepts: simple timer, periodic timer, and heartbeat timer.
The simple timer produces an event at a given system time or
after a given interval. It is provided by RTimer. This
service is wrapped in an active object by CTimer.
A periodic timer produces a sequence of events at a specified
interval. The application is called through a callback
(TCallBack) when they occur. It is provided by
CPeriodic.
A heartbeat timer is similar to a periodic timer. However, if the application is busy handling another event when the timer event occurs, a periodic timer simple delays delivering the event, while a heartbeat timer will inform the application that it has missed the event.
It is provided by CHeartbeat. Applications
are alerted to timer events through implementing an interface
MBeating.