Set the timesetevent event before the timer

You did not told us about the kind of your threads (like Windows theads or Linux pthread).

But I assume that your thread is already checking for events like stop (when terminating the application) or for starting and resetting the timer. If so, just implement another event that simply calls the callback function when triggered.

If not, I suggest to do so at least for stopping. When your application terminates it should also stop all child threads. Otherwise those would run until returning by themself.

With Windows use WaitForSingleObject resp. WaitForMultipleObjects. With pthreads use pthread_cond_wait or pthread_cond_timedwait. You can also use the timeout value of those functions to implement the timer (if not already doing so).

Implementing a stop event is usually covered by tutorials about a specific thread type. Once using such, adding another event for other purposes is quite simple.