PRB: RELEASE May Not Remove OLE Objects from Memory

ID: Q138398

The information in this article applies to:

Microsoft Visual FoxPro for Windows, versions 3.0, 5.0, 5.0a, 6.0

SYMPTOMS

After creating an OLE object using the CREATEOBEJCT() function, releasing that object does not remove the OLE application session from memory.

RESOLUTION

For Visual FoxPro to remove certain OLE application session objects from memory, the OLE application must be terminated. For example, after running the following code, three instances of Microsoft Excel remain in memory:


   FOR i = 1 TO 3

       oObject = CREATEOBJECT('Excel.Application')
       RELEASE oObject

   ENDFOR

To end each Microsoft Excel session before reentering the FOR loop, the Microsoft Excel session must first be terminated. For example:


   FOR i = 1 TO 3

       oObject = CREATEOBJECT('Excel.Application')
       oObject.Quit
       RELEASE oObject

   ENDFOR

In this example, Microsoft Excel is told to quit, and then the code releases the memory variable in Visual FoxPro by using the oObject.Release command. Quit is a method that Microsoft Excel recognizes and can act upon, the actual method for your OLE automation application may differ.

STATUS

This behavior is by design.

MORE INFORMATION

The OLE Automation release method is program specific. In the previous example, Microsoft Excel was used. Microsoft Excel version 7.0 is designed to remain in memory after a OLE object is released. However, other programs may behave differently. For example, Microsoft Word version 7.0 terminates with just a RELEASE command.

For more information on how your program will handle an OLE Automation RELEASE command, please refer to that program's documentation or refer to the vendor of that program.

Steps to Reproduce Behavior

Run this code:


   FOR i = 1 TO 3
      
       oObject = CREATEOBJECT('Excel.Application')
       WAIT WINDOW 'Created Excel Object' + STR(i)
       RELEASE oObject

   ENDFOR

View the Windows Task List, and notice that three sessions of Microsoft Excel remain in memory.

Additional query words: VfoxWin kbvfp300 kbvfp500 kbvfp500a kbvfp600

Keywords :
Version : WINDOWS:3.0,5.0,5.0a,6.0
Platform : WINDOWS
Issue type : kbprb