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From: "Randy Brukardt" <randy@rrsoftware.com>
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Subject: Re: Timing Block of GNAT code in milliseconds
Date: Mon, 25 Apr 2005 17:56:32 -0500
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Date: 2005-04-25T17:56:32-05:00
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"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
news:ei2meksw8if6.11hcrgpc1osq5$.dlg@40tude.net...
> On 24 Apr 2005 19:57:24 +0100, Simon Wright wrote:
...
> > I don't know about Windows NT.
>
> I presume Real_Time uses Windows' performance counter which never jumps.
> But I have no idea how Calendar behaves, especially in presence of some
> external time synchronization software like NTP.

They both use the Window's performance counter; the code is shared as I
recall. The base time is determined from the usual Windows system calls, and
the performance counter is used to provide an offset.

But the performance counter can jump - just that it does so forward. GNAT
has a workaround for that, but of course you lose some accuracy if it has to
use the workaround.

                     Randy.