UIEvent timestamp

When handling a UIButton touch, you are given a UIEvent object. The UIEvent object has a timestamp which the Apple documentation states as being "the time that the event was created" (UIEvent Class Reference). In the documentation on the Main Event Loop, it states that: "The application object obtains the topmost object in the event queue, converts it to a开发者_如何学Cn event object (UIEvent) ..."

Does [UIEvent timestamp] refer to the time at which the UIEvent object is created (i.e. after processing the touch event off of the main run loop and hance not remotely real-time) or does it refer to the time that the underlying touch object was created (and hence as close as possible to representing the actual time of the user touch9?

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If you want to check, setup a view to log the timestamps of the touches, and then configure a button to lock the main thread for a few seconds (get a for loop to count to a 100 million).

While the main thread is spinning, tap your logging view, then examine the timestamps- if they're evenly spaced the OS does the timestamp, and it's accurate.