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QueryPerformanceCounter()

Started by jho Oct 25, 2000 at 7:15 PM 3 replies 300+ views

Original Post

Oct 25, 2000 at 7:15 PM

Hi, I got the number of ticks from QueryPerformanceCounter(), how do I convert it to Milli-Second? Do I use QueryPerformanceFrequency() to get the clock Frequency, and go ticks / frequency / 1000.0?

Julio

Oct 25, 2000 at 7:24 PM

QPC returns microseconds. so just multiply by 1000.

JoeMont001@aol.com

www.polarisoft.n3.net

Sly

Oct 25, 2000 at 7:34 PM

Is QueryPerformanceCounter() guaranteed to return microseconds? The documentation does not say so, and if so, why would there be a QueryPerformanceFrequency() function? Do not rely on the frequency being in microseconds. It may change between different hardware.

QueryPerformanceFrequency() returns the number of counts per second. So in terms of a second, divide the count by the frequency. Then to get milliseconds, multiply by 1000.

((float)count / (float)frequency) * 1000

Steve 'Sly' Williams
Tools Developer
Krome Studios

jho

Author

jho

Oct 25, 2000 at 10:23 PM

He''s wrong, QPC returns ticks, you figure out mircoseconds by using Freq. * 1000? are you sure? Then it''s saying I used 150,000 ms to do a cycle. I didn''t feel THAT LONG. more like 150 ms.

Knarkles

Oct 26, 2000 at 1:32 AM

It''s count / freq / 1000.0.

-Jussi

(quote space for sale (for free))

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