WD: Shell Command Doesn't Wait for Application to Finish

• Microsoft Word for Windows, versions 2.0, 2.0a, 2.0a-CD, 2.0b, 2.0c, 6.0, 6.0a, 6.0c
• Microsoft Word for Windows 95, versions 7.0, 7.0a

SUMMARY

When you use the Shell command to run another program from a WordBasic macro, Word does not wait for the shelled program to finish running before it processes the rest of the macro.

MORE INFORMATION

WordBasic macro processing is considered "asynchronous." This means that macro commands are executed independently of any timing process, such as a clock. Macros do not wait for a shelled program to finish before executing the next command. This can cause problems in your macro, particularly if the subsequent commands rely on processing performed by the shelled program.

WARNING: ANY USE BY YOU OF THE CODE PROVIDED IN THIS ARTICLE IS AT YOUR OWN RISK. Microsoft provides this macro code "as is" without warranty of any kind, either express or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.

Word versions 7.0, 7.0a

When you use Word 7.x with Windows 95 or Windows NT, the following macro will test to see if an application is still running and won't continue on until the test application has finished running:

   Sub MAIN
      test = AppIsRunning("app string")
         While test = - 1
            test = AppIsRunning("app string")
         Wend
      MsgBox "app has quit"
   End Sub

Word versions 2.0, 6.0

The following WordBasic user-defined function, WaitShell(), uses the Windows function GetModuleUsage() to determine if the shelled application has terminated. If the WinExec() function is successful in starting the program, it returns a module handle which identifies the instance of the loaded application. When the application is no longer running, the module handle will be invalid and GetModuleUsage() will return a value of 0. WaitShell() loops until the module handle is invalid, at which point the remaining macro commands are executed.

   Declare Function WinExec Lib "kernel"(lpszCmdLine$, fuCmdShow As \
   Integer) As Integer
   Declare Sub Yield Lib "kernel"()
   Declare Function GetModuleUsage Lib "kernel"(hInst As Integer) As \
   Integer

   Sub MAIN
      WaitShell("MYPROG.EXE")
      MsgBox "Done."
   End Sub

   Sub WaitShell(szAppToRun$)
      hInst = WinExec(szAppToRun$, 1)
      While GetModuleUsage(hInst) > 0
         Yield   'Waiting
      Wend
   End Sub

   Declare Function GetModuleUsage Lib "Kernel"(hModule As Integer) \
   As Integer
   Declare Function WinExec Lib "kernel"(lpszCmdLine$, fuCmdShow As \
   Integer) As Integer
   Declare Sub WaitMessage Lib "User"()

   Sub MAIN
      WaitShell("MYPROG.EXE")  'MYPROG.EXE is any program to run
      MsgBox "Done."
   End Sub

   Sub WaitShell(szAppToRun$)
      hMod = WinExec(szAppToRun$, 1)
      If(hMod > 32) Then
         While(GetModuleUsage(hMod))
            WaitMessage()
         Wend
      Else
         MsgBox "Unable to start the Application"
      End If
   End Sub

REFERENCES

"Microsoft Windows Programmer's Reference," volume 2: Functions, pages 404, 979, and 983