DOCUMENT:Q74445  12-NOV-1999  [win16sdk]
TITLE   :Opening Files, Compatibility Mode and Windows
PRODUCT :Microsoft Windows Software Development Kit
PROD/VER:WINDOWS:3.0,3.1
OPER/SYS:
KEYWORDS:kb16bitonly

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The information in this article applies to:

 - Microsoft Windows Software Development Kit (SDK) versions 3.0, 3.1 
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SUMMARY
=======

Opening a file in compatibility mode is a very unfriendly action in a
multitasking environment such as Windows. There is never any need to do so;
compatibility mode provides support for old MS-DOS (non-Windows) applications
however it does not provide additional functionality.

Use the following four guidelines for opening files:

1. Do not use the _lcreate function, it opens files in compatibility mode. If it
   is necessary to create a file, immediately close the file and then reopen it
   with the _lopen function.

2. Do not use the OF_SHARE_COMPAT option with the _lopen or OpenFile functions.
   Instead, use one of the other OF_SHARE defines. If no OF_SHARE value is
   specified, the file is opened in compatibility mode.

3. When creating a file using MS-DOS interrupts 3Ch or 5Bh, after creating the
   file, close it and then open it again. The create leaves it in compatibility
   mode.

4. When opening a file (MS-DOS interrupts 3Dh or 6Ch), make sure that the file
   is NOT opened in compatibility mode.

When specifying the open mode and share, do not request more access than
required. If a file will only be read, open it in read-only mode EVEN IF
EXCLUSIVE ACCESS IS REQUESTED. Do not lock out other access unnecessarily. If an
application will only read a file, allow other applications to read the file as
well.

Finally, be open to alternatives when opening a file. If a file is being opened
to display its contents and an open READ-ONLY, DENY-WRITE fails, try an open
READ-ONLY, DENY-NONE.

Additional query words: 3.00 3.10

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Keywords          : kb16bitonly 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK300 kbWinSDK310
Version           : WINDOWS:3.0,3.1

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