Using DDE to Check If Another Windows Application Is Open

ID: Q108681

The information in this article applies to:

Microsoft Visual FoxPro for Windows, version 3.0
Microsoft FoxPro for Windows, versions 2.5, 2.5a, 2.5b

When you are using dynamic data exchange (DDE) commands programmatically, there may be times when you have to determine if a session of an application is already running. DDESetOption() and DDEInitiate() can be used determine if a application is running or not.

For example, the following code determines if Microsoft Excel is already open:

   =DDESetOption("Safety",.f.)         && This turns off the message box
                                       && so that the program will
                                       && not be interrupted.
   openapp=DDEInitiate("Excel","System")

   IF openapp < 0                       && Any negative number returned
                                        && by DDEInitiate() means that a
                                        && channel could not be opened.
      RUN/N C:\EXCEL\EXCEL.EXE
   ENDIF

Additional query words: VFoxWin FoxWin 2.50

Keywords          : FxinteropDde 
Version           : 2.50 2.50a 2.50b
Platform          : WINDOWS 
Issue type        :

Microsoft KB Archive/108681

Using DDE to Check If Another Windows Application Is Open