Microsoft KB Archive/176765

= BUG: Placing Icons in Picture Object Causes Memory Leak =

Article ID: 176765

Article Last Modified on 5/10/2003

-

APPLIES TO


 * Microsoft Visual FoxPro 3.0b Standard Edition
 * Microsoft Visual FoxPro 5.0 Standard Edition
 * Microsoft Visual FoxPro 5.0a
 * Microsoft Visual FoxPro 6.0 Professional Edition

-



This article was previously published under Q176765



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.



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.

