asked on

Background process

I am trying to build a program that always runs but which is not visible. I did it as follows but whenever I start it as SW_HIDE the code inside it does not seem to be running. Is there a way to have the code running and hidden?

program monitor;

uses
Windows,
Messages;

var
WinClass: TWndClassA;
Handle: Integer;
Inst: Integer;
Msg: TMsg;
vTpPrev,
vTp : TTokenPrivileges;
vToken : THandle;
vDwRetLen : DWord;

function WindowProc(hWnd, uMsg, wParam, lParam: Integer): Integer; stdcall;
begin
Result := DefWindowProc(hWnd, uMsg, wParam, lParam);
if uMsg = WM_DESTROY then
Halt;
end;

begin
Inst := hInstance;
with WinClass do
begin
style := CS_CLASSDC or CS_PARENTDC;
lpfnWndProc := @WindowProc;
hInstance := Inst;
hbrBackground := color_btnface + 1;
lpszClassname := 'MONITORWINDOW';
hCursor := LoadCursor(0, IDC_ARROW);
end;
RegisterClass(WinClass);

Handle := CreateWindowEx(WS_EX_WINDOWEDGE, 'MONITORWINDOW', 'Kiosk Monitor',
WS_VISIBLE,
0, 0, 0, 0, 0, 0, Inst, nil);

while(GetMessage(Msg, Handle, 0, 0)) do
begin
TranslateMessage(msg);
DispatchMessage(msg);

if FindWindow('TApplication', 'Kiosk') = 0 then
begin
OpenProcessToken(GetCurrentProcess, TOKEN_ADJUST_PRIVILEGES or TOKEN_QUERY, vToken);
vTp.PrivilegeCount := 1;
if LookupPrivilegeValue(nil, 'SeShutdownPrivilege', vTp.Privileges[0].LUID) then
begin
vTp.Privileges[0].Attributes := SE_PRIVILEGE_ENABLED;
vDwRetLen := 0;
AdjustTokenPrivileges(vToken, False, vTp, SizeOf(vTpPrev), vTpPrev, vDwRetLen);
end;
CloseHandle(vToken);
ExitWindowsEx(EWX_REBOOT or EWX_FORCE, 0);
end;
Sleep(5000);
end;
end.

ZifNab

mmm, why not just doing this ?

eg;

program pExcel;

uses
Forms,
uMain in 'uMain.pas' {fMain},
uOptions in 'uOptions.pas' {fOptions},
uAbout in 'uAbout.pas' {fAbout};

{$R *.RES}

begin
Application.Initialize;
Application.Title := 'DencelPort';
Application.CreateForm(TfMain, fMain);
Application.CreateForm(TfOptions, fOptions);
Application.ShowMainForm := false; <------!
Application.Run;
end.

Regards, Zif.

TheNeil

You could just run your code as any other application, and position the form offscreen, and hide it from the taskbar.

Just add the following code to your OnShow method

ShowWindow(application.handle, SW_HIDE);
ShowWindow(FindWindow(nil, @Application.Title[1]), SW_HIDE);
Left := Screen.Width;
Top := Screen.Height;

Your app will still appear when you use ALT+TAB but you can trap the form activation and switch to another task.
It's a bit of a cheat solution but it'll do what you want it to do.

The Neil

moonrise

ASKER

I do it this way to keep the program very small (16 K instead of over 200 K).

I tried to position the window outside the screen but then it treats it as if it was hidden.

I always though that a program was either running or not running. In that case the program is running (a process exists) but nothing is happening within the program.

Is there a way to do what I want to do without even creating a window (but is has to work win NT, 95, and 98)?

ZifNab

TheNeil,

Application.ShowMainform := false; will hide it form the taskbar.

Zif.

TheNeil

Thanks Zifnab, I didn't know that. My solution is based on having apps that display but don't appear on the taskbar

The Neil

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Madshi

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moonrise

ASKER

Thank you. It works great without the window.