Difference between revisions of "QueryPerformanceCounter"
From Free Pascal wiki
Jump to navigationJump to searchDieselnutjob (talk | contribs) (Using Windows API Performance Counter) |
(source highlight) |
||
| Line 3: | Line 3: | ||
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 | ||
| − | + | <delphi>unit Unit1; | |
| − | + | {$mode objfpc}{$H+} | |
| − | + | interface | |
| − | + | ||
| + | uses | ||
Classes, SysUtils, FileUtil, LResources, Forms, Controls, Graphics, Dialogs, | Classes, SysUtils, FileUtil, LResources, Forms, Controls, Graphics, Dialogs, | ||
StdCtrls, Windows; | StdCtrls, Windows; | ||
| − | + | ||
| + | type | ||
{ TForm1 } | { TForm1 } | ||
TForm1 = class(TForm) | TForm1 = class(TForm) | ||
| Line 20: | Line 22: | ||
var | var | ||
Form1: TForm1; | Form1: TForm1; | ||
| − | + | implementation | |
| − | + | ||
| − | + | { TForm1 } | |
| − | + | ||
| + | procedure TForm1.FormClick(Sender: TObject); | ||
| + | var | ||
PerformanceCounter: int64; | PerformanceCounter: int64; | ||
PerformanceFrequency: int64; | PerformanceFrequency: int64; | ||
| − | + | begin | |
if QueryPerformanceFrequency(PerformanceFrequency) | if QueryPerformanceFrequency(PerformanceFrequency) | ||
| − | + | and QueryPerformanceCounter(PerformanceCounter) | |
| − | then ShowMessage( | + | then ShowMessage('Freq:' + IntToStr(PerformanceFrequency) |
| − | + | + ', Counter:' + IntToStr(PerformanceCounter)) | |
| − | |||
| − | |||
else ShowMessage('Sorry, performance counters not supported.'); | else ShowMessage('Sorry, performance counters not supported.'); | ||
| − | + | end; | |
| − | + | ||
| − | + | initialization | |
| − | + | ||
| + | {$I unit1.lrs} | ||
| + | |||
| + | end.</delphi> | ||
Revision as of 20:39, 10 February 2011
Maybe the one microsecond timestamp is too long for your program. You can access the Windows API Performance Counter using code such as shown below. Note that this API may not be as reliable as you might hope. For more information see http://www.virtualdub.org/blog/pivot/entry.php?id=106
<delphi>unit Unit1; {$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.</delphi>
