Terminating applications

• Close current Delphi application
• Run an application, wait for it to finish, then destroy it
• Kill All Applications
• My method to close a particular named application
• see also:
  • Delphi Programming Main Index

Close current Delphi application:

• there are several options for closing a Delphi application:
  • NB. "abort" does not terminate an application, it creates a silent exception which gets handled by the exception handler
  • call form.close method of the main form:
    • but this then checks the OnClose routine to see if it can close and if errors arise then close fails
  • call application.terminate:
    • doesn't work for console applications (use Halt instead)
    • this will process the finalization section but not try..finally
  • call halt:
    • this is the more generic way to terminate an application
    • this will process the finalization section but not try..finally
  • create own app killer routine that should definitely destroy the application:
    • eg. procedure KillProcessNow; //in fmxutils.pas
      • var memmgr : TMemoryManager;
      • begin
      • try
      • exitproc := nil; ExceptProc := nil; ErrorProc := nil; SetRaiseList(nil); LibModuleList := nil; ModuleUnloadList := Nil;
      • // ask windows nicely to kill us. (well, as nice as we get here)
      • TerminateProcess(GetCurrentProcess, 0);
      • // what - still here? Surely not, Let's pop the stack
      • while true do 
        • asm 
        • pop eax; 
        • end;
      • finally
      • // we don't believe you could ever get here. but if we do,
      • // well, we'll just make sure that nothing will ever work again anyway.
      • memmgr.GetMem := nil; memmgr.FreeMem := nil; memmgr.ReallocMem := nil; SetMemoryManager(memmgr); end;
      • end;

Run an application, wait for it to finish, then destroy it:

• see example in FMXUtils.pas for function WinExecAndWait which will allow you to run an application such as a DOS application running in a console window, wait for it to complete, then terminate it and then continue with your program.
  • NB. for this to work on a DOS console, you should execute a shortcut to the app. and set the shortcut's property to "Close on Exit"

Kill All Applications:

• this uses the TerminateApp command (in WinAPI ToolHelp) to kill the app but may not free all its resources.

• uses: ToolHelp;
• procedure KillAll;
  • var pTask : PTaskEntry; Task : Bool; ThisTask: THANDLE;
  • begin
    • GetMem (pTask, SizeOf (TTaskEntry));
    • pTask^.dwSize := SizeOf (TTaskEntry);
    • Task := TaskFirst (pTask);
    • while Task do
      • begin
      • if pTask^.hInst = hInstance then
        • ThisTask := pTask^.hTask
      • else TerminateApp (pTask^.hTask, NO_UAE_BOX);
      • Task := TaskNext (pTask);
      • end;
    • TerminateApp (ThisTask, NO_UAE_BOX);
  • end;

My method to close a particular named application:

• uses: ShellAPI;
• procedure TFrmHASFix.CloseAnApplication(Title,AltTitle :String);
• var
  • SwitchWnd, Wnd : hWnd;
  • Style : LongInt;
  • Buff, ProgTitle, AlternativeTitle : Array[0..6] of Char; {limit size to first 6 characters}
• begin
  • StrPLCopy(ProgTitle,Title,6); {convert string title to null-term. char ProgTitle}
  • StrPLCopy(AlternativeTitle,AltTitle,6); {convert string title to null-term. char ProgTitle}
  • {Wnd := EnumWindow(Handle,)}{is this a better tool????}
  • Wnd := GetWindow(Handle, gw_HWndLast);
  • GetWindowText(Wnd,buff,sizeof(buff)); {initialise buff}
  • While ((Wnd <> 0) and not((Buff = ProgTitle) or (Buff = AlternativeTitle))) do
    • {get list of all open windows except this programs window handle}
    • begin
    • if (Wnd <> Handle) and isWindowVisible(Wnd) and (GetWindow(Wnd, gw_Owner) = 0) and (GetWindowText(Wnd,buff, sizeof(buff)) <> 0) then
      • GetWindowText(Wnd,buff,sizeof(buff));
    • if ((buff = ProgTitle) or (Buff = AlternativeTitle)) then
      • begin
      • postMessage(Wnd, $10, 0, 0);{gives window close command but closure is under application control}
      • {ToolHelp.TerminateApp(Wnd,NO_UAE_BOX); }{forcibly closes app but may not free all resources}
      • {DestroyWindow(Wnd);}{close application - is there a better way???}
      • showMessage('One instance closed');
      • end;
    • Wnd := GetWindow(Wnd, gw_hWndPrev);
    • end;
• end;

Close an external application using WM_CLOSE:

• NB. this will not force closure if target application prompts user such as "Save changes?"
• hnd : FindWindow(nil, PChar('EQuery Sender'));
• if hnd = 0 then exit; //sender application was not running
• if not postmessage(hnd, WM_CLOSE, 0, 0) then
  • Application.messageBox('Warning! Sender application did not close.', 'Sender did not close', idok);