What happens when CreateWaitableTimer is set for non-existing date/time?

Question

The Daylight Saving Time (United States) in 2013 began at 2:00 AM on Sunday, March 10. So, say, now is March 9, 2013 and I call the following API on an already created waitable timer handle:

FILETIME ftWhen = //Points as absolute time to March 10th, 2013, at 2:10 AM
SetWaitableTimer(hTimer, ftWhen, 0, NULL, NULL, TRUE);

March 10th, 2013, 2:10 AM is a non-existent time because the time will be adjusted one hour ahead so instead of 2 AM it will be 3 AM.

So my question, what will happen to my timer? (I can't seem to find documentation for this case.)

Answer 1

I suspect you already know the answer to your question, because your comment explicitly states:

// Points _as absolute time_ to March 10th, 2013, at 2:10 AM

So you're aware that the documentation for SetWaitableTimer() says:

Be sure to use a UTC-based absolute time, as the system uses UTC-based time internally.

Since UTC does not care about DST whatsoever, your timer will be triggered on March 10th, 2013, 3:10 AM, your local time.

Answer 2

SetWaitableTimer expects the pDueTime to be given in UTC; so there's no way to call it with such a non-existing date/time.