FIX: Insufficient Memory Errors Using OLE Controls

• Microsoft Visual FoxPro for Windows, version 3.0

SYMPTOMS

Under some circumstances, using OLE controls and then repeatedly running the form that contains the OLE controls may result in a loss of system resources.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article. This problem was corrected in FoxPro 3.0b for Windows.

MORE INFORMATION

The following steps will replicate the resource leak in Windows 3.1 or in Windows NT. Before trying this example, you should save any information you have open in Visual FoxPro.

Steps to Reproduce Problem

• Microsoft Word 6.0 or later must be installed.



• On the Tools under the Controls option, you have both the Outline and Microsoft Word Document controls installed.

1. Create a new program file that holds the following code:

   
      FOR i = 1 TO 50000
        Formstr = "TESTFRM"
        Loopstr = "#" + STR(i,3) + ":  "
   
        WAIT loopstr + "Modifying form" WINDOW NOWAIT
        MODIFY FORM (formstr) NOWAIT
        WAIT loopstr + "Modifying form" WINDOW TIMEOUT 2
        RELEASE (formstr)
        CLEAR WINDOW
        CLOSE ALL
        *
        WAIT loopstr + "Running form" WINDOW NOWAIT
        DO FORM (formstr)
        WAIT loopstr + "Running form" WINDOW TIMEOUT 2
        RELEASE (formstr)
        CLEAR WINDOW
        CLOSE ALL
        *
        WAIT loopstr + "Delaying 2 seconds..." WINDOW TIMEOUT 2
        WAIT loopstr + ;
           "Memory handles in use = " + STR(VAL(SYS(1011)),4) WINDOW
   
        TIMEOUT 2
      ENDFOR 




2. In the Command window, type:

   
      CREATE FORM TESTFRM 




3. In the Init event of the form, place the following code:

   
      Public rval
   
      rval=getobject("","word.basic")
      Thisform.olecontrol2.doverb(0)
      rval.insert("Hello")
      rval.insert("Hello1")
      rval.insert("Hello2")
      rval.insert("Hello3")
      rval.insert("Hello4")
   
      Thisform.olecontrol1.additem("Line1")
      Thisform.olecontrol1.additem("Line2")
      Thisform.olecontrol1.additem("Line3")
      Thisform.olecontrol1.additem("Line4")
      Thisform.olecontrol1.additem("Line5") 




4. Place an Outline control on the form. Do not change any default settings.



5. Place a Word Document control on the form, and type some text in it.



6. Run the code. On some versions of Win32s (Prior to version 1.25) Visual FoxPro will quit at around 870 iterations; on Windows NT it will quit at around 2,700 iterations.

Additional query words: VFoxWin buglist3.00 fixlist3.00b crash OLE control OLECONTROL

Keywords : FxinteropOle
Version : 3.00
Platform : WINDOWS
Issue type :