XTENSION: Extension DLL for File Manager

XTENSION is an extension dynamic-link library (DLL) that
adds administration support features such as file and disk
utilities to Microsoft(R) Windows(TM) File Manager.
XTENSION contains an entry point to process menu commands
and notification messages sent by File Manager and can
retrieve information about File Manager windows.

XTENSION adds a menu called Extension to File Manager and
processes all messages that File Manager sends to an
extension DLL. It also creates a status window using the
DLL's instance handle and adds the following commands to
the File Manager Extension menu:

>  Status Window: Shows/hides status window.

>  Selected File(s) Size: Displays disk space taken by the
files.

>  Selected Drive Info: Displays selected drive
information.

>  Focused Item Info: Displays the name of the selected
item.

>  Reload Extension: Reloads this extension.

>  Refresh Window: Refreshes File Manager's active window.

>  Refresh All Windows: Refreshes all File Manager
windows.

>  About Extension: Displays About dialog box.

To load XTENSION.DLL as a File Manager extension, add the
following lines to the WINFILE.INI initialization file:

    [AddOns]
    SDK Demo Extension=<path to XTENSION.DLL>

File Manager installs the extensions that have entries in
 the [AddOns] section of WINFILE.INI. Each entry consists
of a tag and a value.

The File Manager extensions are new in Microsoft Windows
version 3.1. For information on relevant functions and
messages, see the Windows version 3.1 Software Development
Kit (SDK) "Programmer's Reference" manual.

XTENSION was built and tested under Microsoft Windows
version 3.1.

KEYWORDS: FMExtensionProc; FM_GETFOCUS;
FM_REFRESH_WINDOWS; FMEVENT_INITMENU; FMEVENT_LOAD;
FMEVENT_SELCHANGE; FMEVENT_UNLOAD; FMEVENT_USER_REFRESH;
FMS_GETDRIVEINFO; FMS_GETFILESEL
