Les Bell and Associates Pty Ltd
PO Box 173, Frenchs Forest, NSW 1640 Australia
Tel: +61 2 9451 1144 Fax: +61 2 9451 1122

Using REXX to Repair and Control the Desktop

The Workplace Shell is extremely powerful and and customisable, and this is at once a blessing and a curse. It means that support staff can present the user with a customised desktop which is oriented towards their tasks, but it also means that the user can completely rearrange things at best, or delete important objects at worst. We need ways to work around these problems.

Utilities like DeskMan/2 allow the ad-hoc manipulation of objects to change their settings and styles. However, this technique is tedious when a lot of repair work has to be done, or when extensively customising desktops for a number of user machines.

The real pro power technique is to create program reference objects for your OS/2 and DOS apps by using a small REXX program which can set all the appropriate keyname-value pairs in the object's setup string. You want either the SysCreateObject() or the SysSetObjectData() functions. Here's the skinny:

The SysCreateObject() function syntax is:

The class is the workplace shell class for the object you are creating (as a text string). Useful classes include:

• WPDataFile
• WPProgramFile
• WPCommandFile
• WPFolder
• WPClock
• WPSchemePalette
• WPColorPalette
• WPFontPalette
• WPProgram
• WPPrinter
• WPShadow
• WPNetLink

The title is just any string you want as the title for the object.

The location is the object ID of the place where you want your object created. Most useful is "<WP_DESKTOP>", but there are others. If you want to know the good ones, take a look inside the \OS2\INI.RC file - they're all the things in angle braces <>. Most objects created as you use the Workplace Shell have numeric object ID's which are difficult to find out, but folders you create yourself (see below) can be given symbolic ID's. Also objects on disk - that is, which are subclasses of WPDataFile - can be referred to by their pathname, e.g. "C:\Desktop\MyFolder\DATABASE.DBF".

Now, the interesting part - the setup string. All kinds of things can go in here. It's a long string, that takes the form of "key=value;key=value;key=value". Here are the possible key-value pairs for the WPProgram class (i.e. program reference objects):

Example:

setup_string="PROGTYPE=VDM;EXENAME=C:\EDIT.EXE;
                  ASSOCFILTER=*.DOC,*.TXT;ASSOCTYPE=Plain Text;
                  SET DOS_DEVICE=1.SYS,2.SYS;
                  SET PATH=C:\FRED"

Lastly, the options: well, usually that's just "r" to replace any existing object, but it could be "f" to fail if the object already exists or "u" to update any existing object.

For more details, look up SysCreateObject in the REXX online help (VIEW C:\OS2\BOOK\REXX.INF).

Bear in mind that if you launch a Presentation Manager application, it may well contain logic that reads its previous window location and size from wherever it stored it (OS2.INI) when it last shut down, and this will override MAXIMIZED=TRUE. Or it might size itself to be 3/4 of the desktop - that's quite common. However, especially in the first case, you probably don't have a problem with it starting too small.

Here's a sample program fragment, taken from the INSTALL.CMD I wrote to go on the course diskette from the course I'm teaching this week:

--------------%< Cut here %<------------------------

/* REXX Script to install "OS/2 Support" Folder */
'@echo off'
if arg(1,'O') then do
  say "Usage: Install d:"
  exit
end
PARSE UPPER ARG dest

/* The following two lines are necessary for the SysCreateObject() function to be accessible */
call RxFuncAdd 'SysLoadFuncs','RexxUtil','SysLoadFuncs'
call SysLoadFuncs
rc = SysMkDir(dest'\OS2MAINT')
if rc \= 0 & rc \= 5 then do
  say "Error creating \OS2MAINT directory"
  say "rc = "rc
  exit
end

dest        /* Changes to the target drive */
'cd \os2MAINT'
/* Unzip and copy the various files from A: */
'copy a:unzip.exe'
'unzip a:fenx2'
'unzip a:inimt20d'
'unzip a:hpfopt'
'unzip a:pmmine'
'unzip a:txtfiles'
'unzip a:asteroid'
'copy a:*.cmd'
'copy a:*.zip'

/* Create the "OS/2 Support" folder */
rc = SysCreateObject("WPFolder", "OS/2 Support", "", "OBJECTID = ; OPEN=ICON", "r")

rc = SysCreateObject("WPProgram", "IniMaint", "", "EXENAME="dest"\OS2MAINT\INIMAINT.EXE; PROGTYPE=PM;STARTUPDIR="dest"\OS2MAINT", "r")

rc = SysCreateObject("WPProgram", "File Phoenix", "", "EXENAME="dest"\OS2MAINT\PHOENIX2.EXE;PROGTYPE=PM;STARTUPDIR="dest"\OS2MAINT", "r")

rc = SysCreateObject("WPProgram", "PM Mines", "", "EXENAME="dest"\OS2MAINT\PMMINE.EXE;PROGTYPE=PM;STARTUPDIR="dest"\OS2MAINT", "r")

rc = SysCreateObject("WPProgram", "AlarmPro", "", "EXENAME="dest"\OS2MAINT\ALRMPRO.EXE; PROGTYPE=PM;STARTUPDIR="dest"\OS2MAINT", "r")

--------------%< Cut here %<------------------------

OK, with a little hacking and insertion of the correct parameters in the SysCreateObject() function calls, you should be able to create program reference objects that behave the way you want - though see the code fragment at the end of this file first.

Now to SysSetObjectData(). If you've already created the object, and know its ID, then you can change the setup string using this function call. The syntax is:

  pszSetupString="TITLE=MYObject;ICONFILE=myobj.ico;HELPPANEL=132;
                 TEMPLATE=YES;NODELETE=NO"

/* REXX program to create a program reference object */
call RxFuncAdd 'SysLoadFuncs','RexxUtil','SysLoadFuncs'
call SysLoadFuncs

title="Insert your title here"
location=""
setup="EXENAME=c:\somewher\myprog.exe;PROGTYPE=WINDOWABLEVIO;STARTUPDIR=C:\OS2;MAXIMISED=YES"

rc = SysCreateObject("WPProgram", title, location, setup, "r")