PRB: Memory Leak Passing Arrays from VBScript to VFP (193724)


The information in this article applies to:

  • Microsoft Visual FoxPro for Windows 6.0
This article was previously published under Q193724

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

  1. 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
  2. Build that project into a COM .dll file named ArrayHandler.dll.
  3. 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>
  4. Place the ArrayHandler.dll on a computer that has Internet Information Server (IIS) and register the COM server.
  5. Place the Active Server Page created in Step 3 in the InetPub\WWWRoot directory on the IIS Server.
  6. 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.
Modification Type:MajorLast Reviewed:7/1/1999
Keywords:kbprb KB193724
©2002 Microsoft Corporation. All rights reserved.