On Tue, 22 Feb 2011, Bo Berglund wrote:
On Tue, 22 Feb 2011 08:50:33 +0100 (CET), Michael Van Canneyt
<[email protected]> wrote:
I should have added that instead of a sawtooth like noise component
using Frac(Now()) * 24*3600 to get the second since midnight gives
random noise in the seconds values of about 3-4 ms.
Another observation is that there seems to be no data smaller than ms.
If I format this value as a float with more decimals than 3 I always
only see zeroes.
That is logical, since TDateTime only is accurate to millisecond precision.
Granted that, but right now I am mostly interested in finding a way to
time an external event source such that I can measure the time between
events.
After googling a bit I have come up with the following, which is a
variation of a delay function that I created years ago in Delphi to
enable me to output pulses that are timed to milliseconds.
The delay is now converted to a time retrieval function:
function TForm1.GetMillisecondTime: Int64;
var
Freq,
Ts: Int64;
begin
QueryPerformanceCounter(Ts);
QueryPerformanceFrequency(Freq);
if (Ts = 0) or (Freq = 0) then exit;
Freq := Freq div 1000;
Result := TS div Freq;
end;
When I try this in Lazarus I get an "Identifier not found" error (not
surprising).
What should I do in order to get this to compile?
Any suitable unit to add to the uses clause?
If you are on windows: add the windows unit.
If you are on another platform: these functions simply do not exist on other
platforms.
Michael.
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