PRB: Memory Leak Passing Arrays from VBScript to VFP

ID: Q193724

The information in this article applies to:

Microsoft Visual FoxPro for Windows, version 6.0

SYMPTOMS

When passing an array from VBScript code to a Visual FoxPro Component Object Model (COM) Server, memory usage increases.

CAUSE

For every STRING or UNITIALIZED array element, you lose one handle and 8 bytes of memory.

RESOLUTION

The following workaround initializes all elements of the array with numeric data or Null before sending it to the COM Server.


<%@ LANGUAGE=VBScript ENABLESESSIONSTATE=False %>
<html>
<body>
<p><b>This is a test</b></p>

<%
dim myarray(30)
for i = 0 to 29
   myarray(i) = 0 'Or Null
next

set ox = Server.CreateObject("arrayhandler.arrayhandler")
response.write ox.myeval("'<br>'+vers(1)+'</br><br> '+time()+" + _
"' </br>'")
response.write  ox.myeval("'<br>UserMem:'+sys(1016) + '</br>'")

ox.DoNothingToArray myarray

set myarray(2) = NOTHING
set myarray(0) = NOTHING
set myarray(1) = NOTHING

set ox = NOTHING
set zzz = NOTHING

%>
</body>
</html>

STATUS

Microsoft is researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

Steps to Reproduce Behavior

In a project named ArrayHandler, add the following code to the Main program:


DEFINE CLASS arrayhandler AS CUSTOM OLEPUBLIC
  PROCEDURE DoNothingToArray
     PARAM myarray
     EXTERNAL ARRAY myarray
     RETURN
  ENDPROC
  PROC mydocmd(p1)
      &p1
  PROC myeval(p1)
      RETURN EVAL(p1)
ENDDEFINE

Build that project into a COM .dll file named ArrayHandler.dll.

Use the following code in an Active Server Page called ArrayTest.asp:


<%@ LANGUAGE=VBScript ENABLESESSIONSTATE=False %>
<html>
<body>
<%
dim myarray(30)
myarray(0) = "blah"

set ox = Server.CreateObject("arrayhandler.arrayhandler")
response.write ox.myeval("'<br>'+vers(1)+'</br><br> '+"+ _
"time() + ' </br>'")
response.write  ox.myeval("'<br>UserMem:'+sys(1016) + '</br>'")

ox.DoNothingToArray myarray

set myarray(2) = NOTHING
set myarray(0) = NOTHING
set myarray(1) = NOTHING

set ox = NOTHING
set zzz = NOTHING

%>
</body>
</html>

Place the ArrayHandler.dll on a computer that has Internet Information Server (IIS) and register the COM server.

Place the Active Server Page created in Step 3 in the InetPub\WWWRoot directory on the IIS Server.

Run the .asp page by typing the following in the Address line of Internet Explorer on the IIS Server and then press ENTER: http://LOCALHOST/ARRAYTEST.ASP

When the page displays, press the F5 key to refresh. Notice the memory increase with each refresh.

Additional query words: kbVFp600 kbCOMt kbISAPI kbInternet kbVBScript

Keywords : kbGrpFox
Version : WINDOWS:6.0
Platform : WINDOWS
Issue type : kbprb