Q132535: PRB: Releasing Object Variable Does Not Close Microsoft Excel

Article: Q132535
Product(s): Microsoft FoxPro
Version(s): 3.0,5.0,5.0a,6.0
Operating System(s): 
Keyword(s): kbvfp300 kbvfp500 kbvfp600
Last Modified: 24-OCT-2000

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 3.0, 5.0, 5.0a, 6.0 
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SYMPTOMS
========

The CREATEOBJECT function can be used to create a reference to an instance of
Microsoft Excel and assign that reference to a variable. However, releasing that
variable does not cause the instance of Excel to quit.

Inadvertently creating multiple instances of Excel can cause a variety of error
messages, depending on the machine configuration and Windows version. These
error messages include:

  "Insufficient Memory"
  "Not enough memory"
  "Page Fault"

RESOLUTION
==========

If you are running Microsoft Excel 5.0, use the following code to close all
instances of Microsoft Excel:

     PROCEDURE xlquit
     local llFlag
     ON ERROR  llFlag = .F. && Exit loop
     llFlag = .T.
     DO  WHILE  llFlag
        y=GETOBJECT (,"Excel.Application")
        y.QUIT
     ENDDO
     ON ERROR   && Set back to default

If you are using Microsoft Excel 7.0, use the following code:

     PROCEDURE xlquit
     DECLARE LONG FindWindowA IN USER32 AS FindA STRING,STRING
     DECLARE LONG SendMessageA IN USER32 AS SendA LONG, LONG, LONG, LONG
     WM_USER = 1024
     hwnd = FindA("XLMAIN", 0)
       DO  WHILE  hwnd > 0
         WhatD= SendA(hwnd, WM_USER + 18, 0, 0)
         y=GETOBJECT (,"Excel.Application")
         y.QUIT
         hwnd = FindA("XLMAIN", 0)
       ENDDO

The code is different because Microsoft Excel 95 contains a bug that was
corrected in later versions.

For additional information, click the article number below to view the article in
the Microsoft Knowledge Base:

  Q153025 FIX: Microsoft Excel 95 Doesn't Respond Correctly to GetObject

NOTE: The DECLARE statements in the above example are case-sensitive and the
functions must be called just as in the example.

STATUS
======

This behavior is by design.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

Run the following code to create five instances of Microsoft Excel, none of which
are visible:

     FOR i = 1 to 5
       x = CREATEOBJECT("Excel.Application")
       RELEASE x
     ENDFOR

Releasing the variable x does not terminate the instance of Microsoft Excel. To
ensure that each instance is terminated, add the following command immediately
before the RELEASE x command:

     x.Quit

To test if an instance of Microsoft Excel exists use this function:

     x=GETOBJECT(,"Excel.Application")  && The first argument is empty

This returns an OLE error if no instance of Microsoft Excel is in memory.

Additional query words: VFoxWin

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Keywords          : kbvfp300 kbvfp500 kbvfp600 
Technology        : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP500 kbVFP600 kbVFP500a
Version           : :3.0,5.0,5.0a,6.0
Issue type        : kbprb

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