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Time Critical Apps

Posted on 1999-01-22
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Last Modified: 2010-04-06
I am looking for a way to force windows to check an application within a certain period.

This does not need to be particularly fast, say every 20milliseconds, but it must occur every 20ms. I don't want other programs to come along and take over processor time such that it turns into 30ms or anything like that

any ideas... I am fairly new at Delphi but want to investigate this

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Question by:jaredc071598
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4 Comments
 
LVL 13

Expert Comment

by:Mirkwood
ID: 1362775
What you can do is increase the process priority.
Take a look at the API below.
BOOL SetPriorityClass(  HANDLE hProcess,        // handle to the process
  DWORD dwPriorityClass   // priority class value);

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LVL 20

Expert Comment

by:Madshi
ID: 1362776
Yes, and SetThreadPriority(GetCurrentThread,...).
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LVL 13

Expert Comment

by:Mirkwood
ID: 1362777
Madshi, you are right.
The priority of the thread is the combination of the thread priority and the process priority. Note that it is a relative number so if somebody has a higher number you are still not garanteed to receive focus every 20ms.

Usually I search for other solutions. Priorities are dirty. If you need it to access hardware, see if there is a buffer. That is much more useful
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Accepted Solution

by:
Almighty_Phoenix earned 100 total points
ID: 1362778
Use the API !

An Example !

uses mmsystem;

var FID:Integer;                 // Handle of MMTimer

procedure TimeCallback(TimerID, Msg:UINT; dwUser, dw1,dw2:DWORD); pascal;
begin
  // your time critical work
end;

// This initializing the Timer
procedure TForm1.RunTimer;
begin
  FID := timeSetEvent(100,0,@TimeCallback,0,TIME_PERIODIC);
end;
// first (100) is the interval (ms)
// second (0) is the accuracy of timer (0 is max)
// third is your callback procedure (not a method !!!)
// 0 is a optional value
// last can be set TIME_ONESHOT (one event) or TIME_PERIODIC
//                                             (intervals)


// This stop the Timer
procedure TForm1.StopTimer;
begin
  if boolean(FID) then timeKillEvent(FID);
end;







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