Using DDE to Check If Another Windows Application Is Open

Last reviewed: April 30, 1996
Article 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, and 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 reference words: VFoxWin 3.00 FoxWin 2.50 2.50a 2.50b
KBCategory: kbinterop kbprg
KBSubcategory: FxinteropDde

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Last reviewed: April 30, 1996
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