DOCUMENT:Q99337  09-JUL-2000  [win16sdk]
TITLE   :PRB: Using ToAscii() in Journal Record Hooks
PRODUCT :Microsoft Windows Software Development Kit
PROD/VER:WINDOWS:3.1
OPER/SYS:
KEYWORDS:kbHook kbInput kbKeyIn kbOSWin2000 kbSDKWin32 kbGrpDSUser kbOSWin310

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

 - Microsoft Windows Software Development Kit (SDK) 3.1 
-------------------------------------------------------------------------------

SYMPTOMS
========

When a journal record hook procedure calls the ToAscii() function, dead keys are
apparently no longer processed correctly due to a side effect.

CAUSE
=====

The current implementation of ToAscii() determines whether the key that is
currently being processed is a dead key; if yes, it collapses the next keystroke
seen in the input stream with the dead key for Windows to display. This
assumption is being made for Windows, which calls the ToAscii() function during
normal processing of keystrokes. Calling ToAscii() in a journal record hook
clears the flag that indicates the presence of a dead key; thus, the key
combination will not be displayed correctly on the screen although it will
appear correctly when the recorded key strokes are played back.

RESOLUTION
==========

The journal record hook procedure should call the ToAscii() function twice with
the same parameters when processing a dead key [that is, the call to ToAscii()
returns -1]. This will reset the dead key flag internally.

Note that the source code for the ToAscii() function is publicly available
because it resides in the keyboard device driver whose source is shipped with
the Windows Device Development Kit (DDK).

Additional query words:

======================================================================
Keywords          : kbHook kbInput kbKeyIn kbOSWin2000 kbSDKWin32 kbGrpDSUser kbOSWin310 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310
Version           : WINDOWS:3.1
Issue type        : kbprb

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

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.