DOCUMENT:Q140108  06-NOV-1999  [win16sdk]
TITLE   :BUG: Opening an AVI file Fails When MCIWnd Is Subclassed
PRODUCT :Microsoft Windows Software Development Kit
PROD/VER:WINDOWS:3.1; :1.1
OPER/SYS:
KEYWORDS:kbmmkbbuglist

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The information in this article applies to:

 - Microsoft Windows Software Development Kit (SDK) 3.1 
 - Microsoft Video for Windows Development Kit, version 1.1 
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SYMPTOMS
========

In an application based on Windows 3.1 where an MCIWnd window is subclassed
(using SetWindowLong API) and an AVI file is opened by MCIWndOpen macro, if the
window is closed (for example, by double-clicking System Menu Box), then no AVI
files may be opened in any MCIWnd window created thereafter. Specifically,
MCIWndOpen returns MCI error code 289 on subsequent calls.

RESOLUTION
==========

The subclassed window can process a WM_CLOSE message to set the original MCIWnd
window procedure back and then forward this message to the original window
procedure as in this sample code:

      WM_CLOSE: SetWindowLong(hsubMCIWnd, GWL_WNDPROC, (DWORD)lpfnOldWndProc);
                return CallWindowProc(lpfnOldWndProc, hsubMCIWnd,
                message, wParam, lParam);
               // lpfnOldWndProc points to the original MCIWnd procedure

STATUS
======

Microsoft has confirmed this to be a bug in the products listed at the beginning
of this article. We are researching this problem and will post new information
here in the Microsoft Knowledge Base as it becomes available.

Additional query words: 3.10 MCIWndCreate MCI MCIAVI alias used unique

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Keywords          : kbmm kbbuglist
Technology        : kbAudDeveloper kbWin3xSearch kbVideoSearch kbSDKSearch kbWinSDKSearch kbWinSDK310 kbVideoDK110
Version           : WINDOWS:3.1; :1.1

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