Difference between revisions of "QueryPerformanceCounter"

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{{QueryPerformanceCounter}}
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Maybe the one microsecond timestamp is too long for your program.
 
Maybe the one microsecond timestamp is too long for your program.
 
You can access the Windows API Performance Counter using code such as shown below.
 
You can access the Windows API Performance Counter using code such as shown below.
 
Note that this API may not be as reliable as you might hope.  For more information see http://www.virtualdub.org/blog/pivot/entry.php?id=106
 
Note that this API may not be as reliable as you might hope.  For more information see http://www.virtualdub.org/blog/pivot/entry.php?id=106
  
<syntaxhighlight>unit Unit1;  
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<syntaxhighlight lang=pascal>
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unit Unit1;  
 
{$mode objfpc}{$H+}
 
{$mode objfpc}{$H+}
 
interface
 
interface
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{$I unit1.lrs}
 
{$I unit1.lrs}
  
end.</syntaxhighlight>
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end.
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</syntaxhighlight>

Latest revision as of 01:15, 24 February 2020

Windows logo - 2012.svg

This article applies to Windows only.

See also: Multiplatform Programming Guide

English (en)

Maybe the one microsecond timestamp is too long for your program. You can access the Windows API Performance Counter using code such as shown below. Note that this API may not be as reliable as you might hope. For more information see http://www.virtualdub.org/blog/pivot/entry.php?id=106

unit Unit1; 
{$mode objfpc}{$H+}
interface

uses
  Classes, SysUtils, FileUtil, LResources, Forms, Controls, Graphics, Dialogs,
  StdCtrls, Windows;

type
  { TForm1 }
  TForm1 = class(TForm)
    procedure FormClick(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end; 
 var
  Form1: TForm1; 
implementation

{ TForm1 }

procedure TForm1.FormClick(Sender: TObject);
var
  PerformanceCounter: int64;
  PerformanceFrequency: int64;
begin
  if QueryPerformanceFrequency(PerformanceFrequency)
    and QueryPerformanceCounter(PerformanceCounter)
    then ShowMessage('Freq:' + IntToStr(PerformanceFrequency)
       + ', Counter:' + IntToStr(PerformanceCounter))
    else ShowMessage('Sorry, performance counters not supported.');
end;

initialization

{$I unit1.lrs}

end.