Applications and Geodes: 4.2 General System Utilities: Using Timers

GEOS SDK TechDocs

4.1 System Clock

4.3 System Statistics and Utilities

TimerStart(), TimerStop(), TimerSleep(), TimerGetCount()

If your geode needs an action to happen on a timed basis, you will want to use a timer. GEOS lets you set up timers that will call a routine or send a message after a given interval has passed. GEOS offers four types of timers:

• One-shot
  A one-shot timer counts a certain number of "ticks." (There are 60 ticks in a second.) It will call a routine or send a message after the specified number of ticks have been counted.
• Continual
  A continual timer counts a certain number of ticks and then resets and counts again. Each time it reaches the specified number of ticks, it calls a routine or sends a message.
• Millisecond
  A millisecond timer is a one-shot timer that counts in milliseconds rather than ticks and calls a routine when time is up (it does not send a message).
• Sleep
  A sleep timer causes the thread that creates it to sleep for a certain number of ticks. The sleep timer is unlike the others in that it does not send a message or call a routine when time is up; it only awakens the sleeping thread.
• Real-time
  A real-time timer is passed the number of days since 1980, the hour, and the minute of the event. On hardware platforms that support such a thing, GEOS will wake up when the real-time timer goes off. (All other timers are ignored under these conditions.)

All timers except sleep timers are created and started with the routine TimerStart() , and continual timers can be destroyed with TimerStop() . TimerStop() may also be used to prematurely stop a one-shot timer, though if the one-shot sent a message, the message could be in the recipient's queue even after TimerStop() was called. Sleep timers are created and started with TimerSleep() , and they do not need to be stopped.

An additional routine, TimerGetCount() , returns the current system counter. The system counter contains the number of ticks counted since GEOS was started.

GEOS SDK TechDocs

4.1 System Clock

4.3 System Statistics and Utilities