Prevent computer logging out

[KodeZwerg]

...

Put it outside of a method(!)
Use it not in a click, use it in a timer(!)

Exemplary:

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes , SysUtils , Forms , Controls , Graphics , Dialogs , ExtCtrls;
9.  
10. type
11.  
12.   { TForm1 }
13.  
14.   TForm1 = class(TForm)
15.     Timer1: TTimer;
16.     procedure FormCreate(Sender: TObject);
17.     procedure Timer1Timer(Sender: TObject);
18.   strict private
19.  
20.   private
21.  
22.   public
23.  
24.   end;
25.  
26. var
27.   Form1: TForm1;
28.  
29. implementation
30.  
31. {$R *.lfm}
32.  
33. const
34.  ES_CONTINUOUS       = $80000000;
35.  ES_DISPLAY_REQUIRED = $00000002;
36.  ES_SYSTEM_REQUIRED  = $00000001;
37.  
38. function SetThreadExecutionState( EXECUTION_STATE : Cardinal ) : Cardinal; stdcall; external 'kernel32.dll' name 'SetThreadExecutionState';
39.  
40. { TForm1 }
41.  
42. procedure TForm1.Timer1Timer(Sender: TObject);
43. begin
44.   SetThreadExecutionState( ES_SYSTEM_REQUIRED );
45.   SetThreadExecutionState( ES_DISPLAY_REQUIRED );
46. end;
47.  
48. procedure TForm1.FormCreate(Sender: TObject);
49. begin
50.   Timer1.Enabled := True;
51.   Timer1.Interval := 5000;
52. end;
53.  
54. end.

[marcov]

const
 ES_CONTINUOUS       = $80000000;
 ES_DISPLAY_REQUIRED = $00000002;
 ES_SYSTEM_REQUIRED  = $00000001;

function SetThreadExecutionState( EXECUTION_STATE : Cardinal ) : Cardinal; stdcall; external 'kernel32.dll' name 'SetThreadExecutionState';[/code]

Added to trunk.

[Mr.Madguy]

...

Put it outside of a method(!)
Use it not in a click, use it in a timer(!)

Exemplary:

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes , SysUtils , Forms , Controls , Graphics , Dialogs , ExtCtrls;
9.  
10. type
11.  
12.   { TForm1 }
13.  
14.   TForm1 = class(TForm)
15.     Timer1: TTimer;
16.     procedure FormCreate(Sender: TObject);
17.     procedure Timer1Timer(Sender: TObject);
18.   strict private
19.  
20.   private
21.  
22.   public
23.  
24.   end;
25.  
26. var
27.   Form1: TForm1;
28.  
29. implementation
30.  
31. {$R *.lfm}
32.  
33. const
34.  ES_CONTINUOUS       = $80000000;
35.  ES_DISPLAY_REQUIRED = $00000002;
36.  ES_SYSTEM_REQUIRED  = $00000001;
37.  
38. function SetThreadExecutionState( EXECUTION_STATE : Cardinal ) : Cardinal; stdcall; external 'kernel32.dll' name 'SetThreadExecutionState';
39.  
40. { TForm1 }
41.  
42. procedure TForm1.Timer1Timer(Sender: TObject);
43. begin
44.   SetThreadExecutionState( ES_SYSTEM_REQUIRED );
45.   SetThreadExecutionState( ES_DISPLAY_REQUIRED );
46. end;
47.  
48. procedure TForm1.FormCreate(Sender: TObject);
49. begin
50.   Timer1.Enabled := True;
51.   Timer1.Interval := 5000;
52. end;
53.  
54. end.

Docs say, that Prev := SetThreadExecutionState(ES_CONTINUOUS or ES_SYSTEM_REQUIRED or ES_DISPLAY_REQUIRED) is enough, so timer isn't needed. But this state should be manually cleared via SetThreadExecutionState(Prev).

[KodeZwerg]

Added to trunk.

Good day, than please like that and not my quick and dirty version 
I was not aware of your action. 

Code: Pascal  [Select][+][-]

1. {$IFDEF MSWINDOWS}
2. type
3.   EXECUTION_STATE = UINT32; //4 byte unsigned int
4.  
5. const
6.   //Away mode should be used only by media-recording and media-distribution
7.   //applications that must perform critical background processing on desktop
8.   //computers while the computer appears to be sleeping.
9.   ES_AWAYMODE_REQUIRED = UINT32($00000040); //Enables away mode. This value must be specified with ES_CONTINUOUS.
10.   ES_SYSTEM_REQUIRED = UINT32($00000001); //Forces the system to be in the working state by resetting the system idle timer.
11.   ES_DISPLAY_REQUIRED = UINT32($00000002); //Forces the display to be on by resetting the display idle timer.
12.   ES_CONTINUOUS = UINT32($80000000);
13.  
14. //If the function succeeds, the return value is the previous thread execution state.
15. //If the function fails, the return value is NULL.
16. //Minimum requirements: Windows XP
17. function SetThreadExecutionState(esFlags: EXECUTION_STATE): EXECUTION_STATE; stdcall; external 'kernel32.dll';
18. {$ENDIF}

That is the more better and full variant 

so timer isn't needed

I do not know to what document you refer, it is just wrong.
Not believe?
Make a test app that set value just once and do nothing, depending on your power configuration your system will go into power saving mode.

[Nicole]

have not read all the answers and risk to give mine twice:
There is a small tool by MS called "MouseMover" or similar.

[KodeZwerg]

have not read all the answers

You not read any answer since what you suggested is already in first reply.

[Mr.Madguy]

I do not know to what document you refer, it is just wrong.
Not believe?
Make a test app that set value just once and do nothing, depending on your power configuration your system will go into power saving mode.

The most obvious docs - are Microsoft's ones.

[Davidous]

Thank you All!

I implemented KodeZwerg's code and it compiles without problem.