DispatchTime - Initializer

I cannot find any initializer of DispatchTime, nor any way to convert DispatchWallTime to DispatchTime.

Use always DispatchWallTime, if you need absolute time.

By the way, do you know why those two distict types are provided in Swift Dispatch library? Both representing dispatch_time_t in GCD.

You manipulate times in ways like

let t = DispatchTime.now() + DispatchTimeInterval.milliseconds(30)

or

let wallt = DispatchWallTime.now() + DispatchTimeInterval.seconds(150)

I know that usage.

GoZoner is talking about how we can manage absolute time as DispatchTime (or DispatchWallTime), not a relative time from now.

By the way, do you know why those two distict types are provided in Swift Dispatch library?

These model the difference between wall time (returned by

gettimeofday

mach_absolute_time

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Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

Thanks, eskimo! I really expect such description would be added to the Standard Linbrary refrences. (A problem of time?)

Can we expect the addition of an initliazer for DispatchTime in the next release?

The problem is that this doesn't seem to be true — at least not on iOS.

In my experiments, `asynchAfter(deadline:)` and `asynchAfter(wallDeadline:)` do exactly the same thing. If you start them at the same time with the same interval, they fire at the same time, no matter what happens in between.

Moreover, `asynchAfter(wallDeadline:)` does not successfully watch the clock. If `asynchAfter(deadline:)` would fire late because the app was suspended for a while, `asynchAfter(wallDeadline:)` fires equally late.

I'd love to be shown wrong. If there's a genuine difference — in fact, not just in theory — I'd like to know what it is.

The problem is that this doesn't seem to be true — at least not on iOS.

That wouldn’t necessarily surprise me but…

If

asynchAfter(deadline:)

would fire late because the app was suspended for a while …

App suspension is not the same as system sleep, and only the latter effects Mach absolute time.

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Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

Indeed. My experimentation suggests that DispatchWallTime on iOS is a synonym for DispatchTime. That's not evil, but it would be nice if the docs would say so.

My experimentation suggests that

DispatchWallTime

on iOS is a synonym for

DispatchTime

.

Thanks for digging into this.

That's not evil, but it would be nice if the docs would say so.

I believe you know what to do here.

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Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"