DOCUMENT:Q176765  22-OCT-2000  [foxpro]
TITLE   :BUG: Placing Icons in Picture Object Causes Memory Leak
PRODUCT :Microsoft FoxPro
PROD/VER::3.0b,5.0,5.0a,6.0
OPER/SYS:
KEYWORDS:kbvfp kbvfp300 kbvfp500 kbvfp500a kbGrpDSFox

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

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

SYMPTOMS
========

A program that loads a series of icon files into the Picture property of a
Visual FoxPro image object causes a memory leak in Visual FoxPro 3.0b, 5.0x, and
6.0. Eventually, the operating system becomes unstable and the computer locks.

CAUSE
=====

Loading the icon files may create a leak in process memory. As the program runs,
increasing amounts of RAM are consumed. When the program starts using virtual
memory, performance suffers and the computer may lock.

RESOLUTION
==========

Currently, there is no resolution, but following are two workarounds:

 - Use a bitmap instead of an icon file to display an image in the Picture
   property.

-or-

 - Use an OLE container control that contains the Visual FoxPro HWND .ocx
   control to display the icon.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article.

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

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

WARNING: Running the code below causes a low memory situation on the computer.
This condition may cause the operating system to become unstable. Close all open
applications and save your data before using this procedure. In Microsoft
Windows 95 and Microsoft Windows NT, press the CTRL+ALT+DEL keys simultaneously
to invoke the Close Dialog window or the Task Manager, respectively.

Create and run a program that contains the following code:

      LOCAL ARRAY laIcons[1,1]
      LOCAL loForm, lnI, lnFile, lnFiles

      loForm = CREATEOBJECT('Form')
      loForm.HEIGHT = 600
      loForm.WIDTH = 200

      FOR lnI = 1 TO 10
      loForm.ADDOBJECT('imgObject' + ALLTRIM(STR(lnI)), 'Image')
      WITH loForm.CONTROLS[lnI]
      .LEFT    = 10
      .TOP     = 10 + (lnI ) * 50
      .WIDTH   = 25
      .HEIGHT  = 25
      .VISIBLE = .T.
      ENDWITH
      ENDFOR

      loForm.ADDOBJECT('lblCounter', 'Label')
      loForm.lblCounter.TOP      = 1
      loForm.lblCounter.LEFT     = 1
      loForm.lblCounter.AUTOSIZE = .T.
      loForm.lblCounter.VISIBLE  = .T.
      loForm.SHOW()
      lnFiles = ADIR(laIcons, HOME() ;
      + 'SAMPLES\GRAPHICS\ICONS\COMPUTER\*.ICO')

      FOR lnI = 1 TO 1000
      loForm.lblCounter.CAPTION = 'Loop :' + PADL(lnI, 4)
      FOR lnFile = 1 TO lnFiles - 10
      loForm.CONTROLS[ 1].PICTURE = ;
      HOME() + 'SAMPLES\GRAPHICS\ICONS\COMPUTER\' + laIcons[lnFile , 1]
      loForm.CONTROLS[ 2].PICTURE = ;
      HOME() + 'SAMPLES\GRAPHICS\ICONS\COMPUTER\' + laIcons[lnFile+1, 1]
      loForm.CONTROLS[ 3].PICTURE = ;
      HOME() + 'SAMPLES\GRAPHICS\ICONS\COMPUTER\'+ laIcons[lnFile+2, 1]
      loForm.CONTROLS[ 4].PICTURE = ;
      HOME() + 'SAMPLES\GRAPHICS\ICONS\COMPUTER\'+laIcons[lnFile + 3, 1]
      loForm.CONTROLS[ 5].PICTURE = ;
      HOME() + 'SAMPLES\GRAPHICS\ICONS\COMPUTER\'+laIcons[lnFile + 4, 1]
      loForm.CONTROLS[ 6].PICTURE = ;
      HOME() + 'SAMPLES\GRAPHICS\ICONS\COMPUTER\'+laIcons[lnFile + 5, 1]
      loForm.CONTROLS[ 7].PICTURE = ;
      HOME() + 'SAMPLES\GRAPHICS\ICONS\COMPUTER\'+laIcons[lnFile + 6, 1]
      loForm.CONTROLS[ 8].PICTURE = ;
      HOME() + 'SAMPLES\GRAPHICS\ICONS\COMPUTER\' + laIcons[lnFile+7, 1]
      loForm.CONTROLS[ 9].PICTURE = ;
      HOME()+'SAMPLES\GRAPHICS\ICONS\COMPUTER\' + laIcons[lnFile + 8, 1]
      loForm.CONTROLS[10].PICTURE = ;
      HOME()+'SAMPLES\GRAPHICS\ICONS\COMPUTER\' + laIcons[lnFile + 9, 1]
      IF INKEY(0.001, 'HM') = 27
      CANCEL
      ENDIF
      ENDFOR
      ENDFOR

The first indication of a memory problem appears when the icons no longer appear
in the individual image objects. The number of iterations before this symptom
appears depends on the amount of physical RAM installed on the computer. Once
the memory leak consumes all the physical RAM, Visual FoxPro begins using
virtual memory. At this point, performance suffers greatly and the operating
system may lock.

REFERENCES
==========

Visual FoxPro Help 3.0b, 5.0, 5.0a; search on: Visual FoxPro HWND Control

Additional query words:

======================================================================
Keywords          : kbvfp kbvfp300 kbvfp500 kbvfp500a kbGrpDSFox 
Technology        : kbVFPsearch kbAudDeveloper kbVFP300b kbVFP500 kbVFP600 kbVFP500a
Version           : :3.0b,5.0,5.0a,6.0
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2000.