Re: SetWaitableTimer confusions

"Igor Tandetnik" <>
Mon, 15 Dec 2008 07:59:41 -0500
"George" <> wrote in message

Manual reset handle, once signalled, remains signalled until reset
with SetWaitableTimer. Automatic reset handle resets to
non-signalled state as soon as a thread successfully finishes a wait
on it.

Why we need to use two status of a timer -- signalled and
un-signalled? What is the usage scenario?

As with any other waitable object (see e.g. CreateEvent) - you wait on
the handle with, say, WaitForSingleObject. This function returns only
when the handle becomes signalled. The object is called "waitable timer"
for a reason, you know.

My confusion is timer is
just an utility to be used to execute task repeatedly, who cares
about the signal or un-signal status?

Well, how do you believe you would associate a "task" with a waitable

Kernel waitable timer is a low-level object. Its only job is to become
signalled at a predetermined time, thus possibly allowing threads
waiting on it to proceed. Any higher-level functionality you will have
to build yourself.
With best wishes,
    Igor Tandetnik

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