Article: Q199538
Product(s): Microsoft C Compiler
Version(s): MACINTOSH:4.0,4.0b
Operating System(s):
Keyword(s): kbDocView kbHWMAC kbMFC KbUIDesign kbVC400bug kbDSupport kbGrpDSMFCATLkbbuglist
Last Modified: 11-MAR-2000
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The information in this article applies to:
- Microsoft Visual C++, Macintosh Cross-Development Addon, versions 4.0, 4.0b
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SYMPTOMS
========
When clicking a disabled scroll bar of a window, the scroll bar becomes enabled.
If the mouse click occurs where the scroll thumb would be, the application
crashes.
CAUSE
=====
There is a bug in the Windows Portability Layer.
RESOLUTION
==========
Set the scroll range to 0, 0 (zero, zero) using SetScrollSizes() or
SetScrollInfo().
STATUS
======
Microsoft has confirmed this to be a problem in the Microsoft products that are
listed at the beginning of this article.
MORE INFORMATION
================
When a window has its scroll bar enabled, and is disabled using the following
code
// hWnd is a handle to window
EnableScrollBar(hWnd, SB_BOTH, ESB_DISABLE_BOTH);
then the scroll bars are enabled if the user generates a mousedown in the
disabled scroll bar. If the mousedown occurs where the scroll thumb would be,
the application crashes with the following error message:
Sorry, a system error occurred.
"myapplication"
Bus error
This problem appears for the scroll bar of a combo box but does not appear for
the scroll-bar control. This fails with both PowerPC and 68KB platforms.
The workaround is to set the scroll range to 0, 0, as demonstrated below:
SCROLLINFO si;
si.cbSize = sizeof(SCROLLINFO);
si.fMask = SIF_RANGE;
si.nMin = si.nMax = 0;
SetScrollInfo(hWnd, SB_HORZ, &si, TRUE);
SetScrollInfo(hWnd, SB_VERT, &si, TRUE);
REFERENCES
==========
(c) Microsoft Corporation 1999, All Rights Reserved. Contributions by Adam Kim,
Microsoft Corporation.
Additional query words: CScrollView CComboBox CScrollBar bus error scrollbar
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Keywords : kbDocView kbHWMAC kbMFC KbUIDesign kbVC400bug kbDSupport kbGrpDSMFCATL kbbuglist
Technology : kbVCsearch kbHWMAC kbOSMAC kbAudDeveloper kbVCXDev400Mac kbVCXDev400bMac
Version : MACINTOSH:4.0,4.0b
Issue type : kbbug
Solution Type : kbnofix
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