Mega Code Archive
High Res Timer (API Function)
<![CDATA[
Title: High Res Timer (API - Function)
Question: When Timer is not good enough
Answer:
Here's a method for calculating a function with the use of a highres timer.
Procedure TForm1.Button1Click(Send: TObject);
var loop1,loop2 : integer;
startcount,
endcount,
frequency : TLargeInteger;
Elapsedtime : Extended;
Begin
QueryPerformanceFrequency(Frequency) {retrieve the freq from highres timer if present}
QueryPerformaceCounter(Startcount); {Start timing}
For loop1 := 0 to 99 do
for loop2 := 0 to 99 do
StringGrid1.cells[loop2,loop1] := inttostr((loop1*100)+loop2); {do something here}
QueryPerformanceCounter(Endcount); {End timing}
Elapsedtime := (Endcount.Quadpart-Startcount.QuadPart)/Frequency.QuadPart;
{Calculates total amount of time the function took to compleet}
Label1.Caption := 'Elapsed time : '+FloatTostr(ElapsedTime)+' seconds.';
End;
Keep in mind that this frequency varies from machine to machine. It all depends on the hardware configuration. It can be usefull for optimizing a part of your code.
Not every machine has a highres timer. Here's some code to check if there is one.
if QueryPerformanceCounter(frequency) then
label1.Caption := 'High Res Timer present.';
else
label1.Caption := 'No High Res Timer present.';
So happy timing!
]]>