Exe instance question

Cor · **Posted:** Wed May 07, 2003 9:15 pm

I have the following situation.

Start test.exe

Start the same program test.exe for the second time

The first instance must be closed and the second must be opened.

Is there a way to do this?

freak · **Posted:** Wed May 07, 2003 9:34 pm

If I remember right, there was a snipped on the Recource Site that does
that. Have a search there, maybe you find it.

You can also have a look at the source of the Editor. It behaves in a
similar way (if a second instance is opened, the second one get's closed)

Timo

Cor · **Posted:** Wed May 07, 2003 9:37 pm

Thanks Freak

Berikco · **Posted:** Wed May 07, 2003 9:44 pm

Here an small example

Code:

ERROR_ALREADY_EXISTS = 183
Global WM_ACTIVATEOLDINST
WM_ACTIVATEOLDINST = RegisterWindowMessage_("WM_ACTIVATEOLDINST_PB")
MutexName$ = "mylittletestapp"

Procedure MyWindowCallback(WindowID, Message, wParam, lParam)  
  Result = #PB_ProcessPureBasicEvents  
  If message = WM_ACTIVATEOLDINST
    CloseHandle_(hMutex)
    OpenConsole()
    PrintN("closing app")
    Delay(2000)
    End
  EndIf
  ProcedureReturn Result  
EndProcedure  

hMutex = CreateMutex_(0, 0, @MutexName$)
If GetLastError_() = ERROR_ALREADY_EXISTS 
  SendMessage_(#HWND_BROADCAST, WM_ACTIVATEOLDINST, 0, 0)
  Delay(100)
EndIf


If OpenWindow(0,100,150,450,200,#PB_Window_SystemMenu,"MyLittleTestApp " + Str(Random(500)))
  SetWindowCallback(@MyWindowCallback()) 
  Repeat
    ev=WaitWindowEvent()
  Until ev=#PB_EventCloseWindow
EndIf

If hMutex <> 0 
 CloseHandle_(hMutex)
EndIf

End

PB · **Joined:** Fri Apr 25, 2003 5:24 pm **Posts:** 7581

> Here an small example

Here's an even smaller example: :twisted:

Code:

; These two lines prevent this app from being run more than once.
; You must put these lines at the start of your app's code (obviously).
MutexID=CreateMutex_(0,1,"YourAppName") : MutexError=GetLastError_()
If MutexID=0 Or MutexError<>0 : ReleaseMutex_(MutexID) : CloseHandle_(MutexID) : End : EndIf
;
; Your app's code now goes here, until quitting time, which executes the next line.
;
CloseHandle_(MutexID) : End

Berikco · **Posted:** Thu May 08, 2003 7:56 am

PB wrote:

> Here an small example

Here's an even smaller example:

Cor wrote:

The first instance must be closed and the second must be opened.

No PB, you did not read the whole question, to fast again.
First closed.....second....
:mrgreen:

PB · **Joined:** Fri Apr 25, 2003 5:24 pm **Posts:** 7581

> No PB, you did not read the whole question, to fast again.
> First closed.....second....

Thade · **Posted:** Sun Aug 03, 2003 3:59 am

Just for curiosity ...

What situation could make it worth to start the same program twice only to close the first one immediately after you started the second one?
Or did I miss the point somehow?
I mean: what can the same program do at its second start what it cannot do at first try?

dagcrack · **Posted:** Thu Mar 11, 2004 1:00 pm

Hmm Dunno! maybe his proggy is a trial release and each time you open it you have less runs to go ? :wink:

Just wondering heh..

Rescator · **Posted:** Thu Jun 16, 2005 12:48 am

Here is a modification of the above code!
It let you do single instance running just like any "good" application!

Run the program, minimize the window. Then run it again!
If all goes well the program won't start again,
but instead message the old instance and restore it and bring it to the foreground!

Only tested on XP Pro, but should behave in a similar way on all windows versions. not entirely sure if W95 behave exactly the same or not, test to be sure!

Code:

ERROR_ALREADY_EXISTS = 183
Global WM_ACTIVATEOLDINST
WM_ACTIVATEOLDINST = RegisterWindowMessage_("WM_ACTIVATEOLDINST_PB")
MutexName$ = "mylittletestapp"

Procedure MyWindowCallback(WindowID, message, wParam, lParam)
 Result = #PB_ProcessPureBasicEvents
 If message = WM_ACTIVATEOLDINST
  ShowWindow_(WindowID,#SW_RESTORE)
  SetForegroundWindow_(WindowID)
  EndIf
 ProcedureReturn Result
EndProcedure

hMutex = CreateMutex_(0, 0, @MutexName$)
If GetLastError_() = ERROR_ALREADY_EXISTS
  SendMessage_(#HWND_BROADCAST, WM_ACTIVATEOLDINST, 0, 0)
  End
EndIf


hwnd=OpenWindow(0,100,150,450,200,#PB_Window_SystemMenu|#PB_Window_MinimizeGadget,"MyLittleTestApp ")
If hwnd
  SetWindowCallback(@MyWindowCallback())
  Repeat
   ev=WaitWindowEvent()
   If showoldwindow
   EndIf
  Until ev=#PB_EventCloseWindow
EndIf

If hMutex <> 0
 CloseHandle_(hMutex)
EndIf

End

I'll leave it up to you as a coding exercise to find out how to send a message to the old (first) app with a filepath. (like many editors do)
Shouldn't be hard, the messaging "example" is already here so. Hehe!

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