DOCUMENT:Q86266  11-JUN-1999  [win16sdk]
TITLE   :DOC: Overview Manual Documents PostAppMessage Incorrectly
PRODUCT :Microsoft Windows Software Development Kit
PROD/VER:WINDOWS:3.1
OPER/SYS:
KEYWORDS:kbdocfix kb16bitonly kbSDKPlatform kbWndw kbWndwMsg

======================================================================
3.10
WINDOWS
kbprg kbdocerr

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

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

SUMMARY
=======

Section 1.1.4 (page 10) of the "Microsoft Windows Software Development Kit:
Programmer's Reference, Volume 1: Overview" manual for version 3.1 documents
that the PostAppMessage function posts a message to an application using its
module handle. This statement is incorrect; PostAppMessage posts a message to an
application using its task handle.

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

Microsoft Windows makes a very important distinction between a task handle and a
module handle. Each instance of an application has exactly one task, which
consists of a stack, a message queue, and an execution state (CPU registers).
However, all instances of an application share the same module, which consists
of the application's executable code and resources.

One cannot post a message to a module for two reasons:

 - A module does not have a message queue; therefore, it cannot process a
   message.

 - Potentially, several application instances (tasks) share a module; therefore,
   a module handle does not identify a unique task to receive the message.

By posting a message to a task handle, the message is sent to only one instance
of an application.

Additional query words: 3.10 SDK docerr

======================================================================
Keywords          : kbdocfix kb16bitonly kbSDKPlatform kbWndw kbWndwMsg 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310
Version           : WINDOWS:3.1

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

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 1999.