Introduction » Time Triggers

Time-based progress actions.

The timed trigger component vt::timetrigger::TimeTriggerManager, accessed via vt::theTimeTrigger() manages and coordinates time-based actions that can be registered by the system and users.

A timed trigger, when registered using the manager, will fire approximately along that period. For instance, if a trigger is registered with a 100ms period, it will be called approximately every 100ms while the vt progress function is being invoked. If the progress function (or vt scheduler) is called infrequently, the triggers may be delayed depending on the period. Also, if large work units are enqueued in the vt scheduler that take longer than the time period, the trigger will fire as often as it can in between these pieces of work (the component does not use interrupts to trigger actions).

To register a trigger, call vt::theTimeTrigger()->addTrigger(100ms, []{ /* my action */});. The addTrigger method returns a handle to the registered trigger that can be passed to vt::theTimeTrigger()->removeTrigger(id); to stop it from firing at a certain point.