Subject:	uclock() counts down?
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Date:	Thu, 13 Feb 2003 09:40:40 -0500
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Thread-Topic:	uclock() counts down?
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From:	"Alex O" <Alex AT compuweigh DOT com>
To:	<djgpp AT delorie DOT com>
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Reply-To:	djgpp AT delorie DOT com

Hi everybody,

I have noticed a strange behavior with uclock() in my program and was just wondering if there is a rational explanation to that.
After some recent changes in the application I have noticed that the time-dependent values on my real-time graphs may flow backwards! I use uclock() to time the change of certain parameters, because they are too fast for clock() (60-100 times per second), and monitoring the return values of uclock() I saw that it in fact may sometimes return smaller values than before for a few calls in a row!
After about a day digging through the code I finally found this strange piece of code:

uclock();
...
inportb(0x40);

which causes this odd behavior. If reading from the port 0x40 (system's timer register) is commented out or placed before the uclock(), everything works OK.

Any thoughts why?

Alex O.

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