SHELL from DOS App

[Walt Decker]

I have a DOS app from which I shell to a PB/DLL app. The PB/DLL app acts as
a tsr to do various disk and registry operations (eg, read long file names,
read the registry to launch other apps to open various types of files). In Win95/
98 it works quite well but with some configurations of Win2000/NT the PB app
grabs the focus and doesn't let go. Is there some way to give up the focus
so that it will return to the calling DOS app?


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[Michael Mattias]

Is there some way to give up the focus ...

When you find that way, please mail a copy of the solution to:

William J.Clinton
New York City, NY


Thank you,
MCM

[Walt Decker]

The strange thing is that, even if I end the PB/DLL app after it has done its thing,
the focus still doesn't return to the DOS app unless I manually go in and terminate
the PB/DLL process. Once I do that, then it works fine by continually SEHLLing
out to the PB/DLL.

I don't have to do that in 95/98. Haven't checked it in ME.

Using the SHELL function in PB one can specify whether the called app has the focus or
not. Should't PB be able to determine whether it has the focus. Incidentally,
the PB app creates no windows of any kind.
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[This message has been edited by Walt Decker (edited May 11, 2001).]

[Scott Turchin]

I think I have some PBDOs code that will regain the focus for you.
I also have some that will maximize the dos session etc...Inter-Sceptre had it all, worked great under 95/98.


As to WHY? Remember you are operating on a true (caugh caugh) 32 bit operating system on NT, whereas 95/98 is a lot of 16 bit stuff, definitely different video and kernel etc...

The only other method would be to grab the window handle of the dos prompt and send it a set focus before terminating the PB/DLl app...

How do you communiate bakc to the dos box, via text file?


Scott

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Scott

[Walt Decker]

Yes, through a text file. Once the PB app starts, all info is passed through 2 text files.
One tells the PB app what to do, the PB app then delets it, and writes the result to
another text file. By having 2 files, all I have to look for are the file names. If they are
present, then the appropriate app takes action.

Unfortunately, the DOS app is in MSPDS. However, if the PBDOS code uses interrupts in
ASM fasion, I can readily translet to something compatible with PDS.



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[Semen Matusovski]

Walt --

Probably, I lost something, but I don't see any problem here.

1) To compile PB/DLL module as console app (for example, using a wrapper, which I posted a week ago).
2) In PB/DLL:
a) to retrieve hwnd of console window (for example, SetConsoleTitle ... FindWindow).
b) to execute GUI part
c) to return focus to console window.
It's not a problem, even if app has no focus (search SetForegroundWindow / AttachThreadInput / SwitchToThisWindow and so on).
But typically GUI app will be finished by pressing any button.
In this moment GUI is foreground and before closing a dialog it's possible to use simple
ShowWindow hWndConsole, %SW_SHOWNA: SetForegroundWindow hWndConsole

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E-MAIL: [email protected]

[Walt Decker]

Semen, I think you did miss something. The PB app does nothing except read directories and the WINNT registry.
It then passes that information back to the PDS app through a file. Once that is done it goes into an infinite loop
until, via a file, it receives a request for more information. When the PDS app is finished, it sends a message to the PB
app to shut itself down and clean up it's own files. There are no windows or GUI's involved in the PB app.

I don't see how compiling the PB app in a wrapper can make it give up the focus so that the PDS app can continue doing
it's thing, but I'll take a look at your posted code. Perhaps in WINNT it will work, NT seems a bit strange anyway.

Walt



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[Lance Edmonds]

The problem is that when a DOS app launches a GUI (or GUI subsystem) app, Windows launches it as a separate Process, and focus may or may not be restored to the DOS app when the GUI app finishes. If the DOS app was running full screen, then it is almost certain the DOS window will not be restored.

However, if you launch a console app from a DOS app, the console app uses the current DOS window, so focus is not lost. Also, it is possibly to synchronously SHELL to a GUI app from a console app (but not from a DOS app), so this may be a simpler solution for you.

I wrote a small app called WINLINK.EXE that is designed to help with this exact issue - restoring the DOS app to the foreground after Synchronously SHELLing to a GUI app. If you'd like a free copy, please just send me a private email mailto:[email protected]@xtra.co.nz[email protected]@xtra.co.nz</A>

PS: I made this offer a few weeks ago, and several folks asked for a copy of WINLINK< but there was one guy whose email bounced several times. If you have asked me for a copy of WINLINK and did not receive it (you know who you are!), please email me again!

Thanks!


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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Semen Matusovski]

Walt --
if Pb/DLL is compiled as console app, it will share dos window.

But I see that your task is much easy.
I wrote simple Turbo Basic app (dos.exe).
Guess, PB DOS will understand it also.

   On Error Goto PrErr1
   Goto Start

 PrErr1:
   Er = 1: Resume Next

 Start:
   Line Input "Type a request to PB/DLL ? ", Buf$
   Do
      Er = 0: Open "Request" For Output As #1
      If Er = 0 Then Exit Loop Else Delay 0.1
   Loop
   Print #1, Buf$: Close #1
   If Buf$ = "Stop" Then End

   Do
      Er = 0: Open "Answer" For Input As #1
      If Er = 0 Then Exit Loop Else Delay 0.1
   Loop

   Line Input #1, Buf$: Close #1: Kill "Answer": Print Buf$: Goto Start

Following PB/DLL exe is a leader

   #Compile Exe
   #Register None
   #Dim All
   #Include "WIN32API.INC"

   Function WndProc(ByVal hWnd    As Dword, ByVal wMsg    As Dword,_
      ByVal wParam  As Dword, ByVal lParam  As Dword) As Long

      Dim i As Long, Buf As String
           
      Select Case wMsg
         Case %WM_CREATE
            i = Shell ("Dos.Exe")
            SetTimer hWnd, 1, 100, ByVal 0&
           
         Case %WM_TIMER
            Open "Request" For Input As #1
            If IsFalse(Err) Then
               Line Input #1, Buf
               Close #1
               Kill "Request"
               If Buf = "Stop" Then
                  PostMessage hWnd, %WM_SYSCOMMAND, %SC_CLOSE, 0
               Else
                  Open "Answer" For Output As #1
                  Print #1, "Reply from PB/DLL : --- " Buf " ---"
                  Close #1
                  SetTimer hWnd, 1, 100, ByVal 0&
               End If
            End If
           
         Case %WM_DESTROY
            PostQuitMessage 0
      End Select
      
      Function = DefWindowProc(hWnd, wMsg, wParam, lParam)

   End Function


   Function PbMain
      Dim Msg As tagMsg, wc As WndClassEx, hWnd As Dword, szClassName As Asciiz * 5
      szClassName = "Test"
      wc.cbSize        = SizeOf(wc)
      wc.lpfnWndProc   = CodePtr(WndProc)
      wc.hInstance     = GetModuleHandle(ByVal 0&)
      wc.hIcon         = LoadIcon  (%NULL, ByVal %IDI_APPLICATION)
      wc.lpszClassName = VarPtr(szClassName)

      RegisterClassEx wc
      hWnd = CreateWindow (szClassName, "Test", 0, 0, 0, 0, 0, 0, 0, wc.hInstance, 0)
      While GetMessage(Msg, ByVal 0&, 0, 0)
         TranslateMessage Msg
         DispatchMessage  Msg
      Wend
   End Function

It's starts DOS part. A program will be finished, when you type Stop instead of "real request".




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E-MAIL: [email protected]

[Semen Matusovski]

I realized my initial suggestion.
TB module

   Print "Press Enter to start GUI ..."
   While Inkey$ <> CHR$(13): Wend
   Shell "GUI.Exe"
   Print "Returned. Press Esc ..."
   While Inkey$ <> CHR$(27): wend

shells GUI.Exe (compiled as "console" in wrapper - '%&)

     #Compile Exe
     #Dim All
     #Register None
     #Include "WIN32API.INC"

     '%&

     Declare Function SwitchToThisWindow (ByVal Long, ByVal Long) As Long

     Sub pSetForegroundWindow(ByVal hwnd As Long)

        Dim hSwitchToThisWindow As Dword, lForeThreadID As Long, lThisThreadID As Long, lReturn As Long

        hSwitchToThisWindow = GetProcAddress(GetModuleHandle("user32.dll"), "SwitchToThisWindow")
        Do
           If hwnd = GetForegroundWindow Then Exit Loop
           lForeThreadID = GetWindowThreadProcessId(GetForegroundWindow, ByVal 0&)
           lThisThreadID = GetWindowThreadProcessId(hwnd, ByVal 0&)
           If lForeThreadID <> lThisThreadID Then
              AttachThreadInput lForeThreadID, lThisThreadID, 1
              SetForegroundWindow hwnd
              AttachThreadInput(lForeThreadID, lThisThreadID, 0
          Else
             lReturn = SetForegroundWindow(hwnd)
          End If
          If hwnd = GetForegroundWindow Then Exit Loop
          Call Dword hSwitchToThisWindow Using SwitchToThisWindow(hwnd, 1) To lReturn
          If hwnd = GetForegroundWindow Then Exit Loop
          ShowWindow hWnd, %SW_MINIMIZE: ShowWindow hWnd, %SW_RESTORE
       Loop
       If IsIconic(hwnd) Then ShowWindow hwnd, %SW_RESTORE Else ShowWindow hwnd, %SW_SHOW
     End Sub

     Function GetConsoleWindow As Long
        Dim lpConsName1 As Asciiz * 256, lpConsName2 As Asciiz * 256, hWndConsole1 As Long, hWndConsole2 As Long

        GetConsoleTitle lpConsName1, SizeOf(lpConsName1)
        Do
           If Len(lpConsName2) >= SizeOf(lpConsName2) Then Exit Function
           lpConsName2 = lpConsName2 + " "
           SetConsoleTitle lpConsName2
           Do
              hWndConsole1 = FindWindow(ByVal %NULL, lpConsName2)
              If hWndConsole1 Then Exit Do Else ApiSleep 40
           Loop
           If hWndConsole1 = hWndConsole2 Then Exit Do
           hWndConsole2 = hWndConsole1
        Loop
        Function = hWndConsole1
        SetConsoleTitle lpConsName1
     End Function

     Function PbMain
        Dim hWndConsole As Long
        hWndConsole = GetConsoleWindow

        Shell "notepad.exe" ' <---- to lose a focus
        pSetForegroundWindow hWndConsole

   End Function

GUI starts Notepad. To continue it's necessary to close notepad's window.
Tested under Win2000 and ME (in window and full screen modes).


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E-MAIL: [email protected]

[Walt Decker]

Thank you, Lance, that clears up the confusion.

Semen, I'll give your wrapper a whirl. Perhaps it will make it possible
for me to regain the focus when the PB app is done.

Thanks for pointing me in the right direction.

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