RE: not able to create indicator as constant -- RPG400-L

On Fri, 21 Apr 2006, Lim Hock-Chai wrote:


My guess would be that there is a service program that contains all the
purch_** procedures.  errMsg variable is a global variable in the
service program.  All purch_** procedures update this field when
encounter error.  purch_error() simply return the errMsg.  Am I close?

You're very close. there's an error message variable that's global to oneof the modules in the purch service program. In addition, there's also anerror number that corresponds to the message, and that's kept in a globalvariable as well.

There's a SetError() subprocedure that the various purch_xxx()subprocedures call to set the global variable. That way, they can set itfrom other modules, if needed. SetError() is exported from the module,but not the service program, so it's not available to anything but modulesin the purch service program.

purch_error() returns the error message, and also has an optional parm toreturn the error number.

In some projects (actually, "purch" happens to be one of them) I take it astep further and create a *MSGF object that contains the error messagesthat purch uses. The error number corresponds to a msgid, and the messagepassed to SetERror() is actually just the MSGDTA for the message file.When I call purch_Error() it combines the MSGDTA with the description inthe message file. This offers a view advantages:

a) When logging a message to a message queue or job log, I have a uniquemessageid and text that fits right into the way the rest of the systemworks.

b) Fatal errors can use *ESCAPE messages, again allowing the caller tomonitor by message id, just like operating system messages.

c) If I want to make my program multi-lingual, I can simply use adifferent message file, since all of the language-specific stuff would bein that.

However, due to the fact that the message file solution adds a lot ofextra complexity, I don't use it for every project. For less importantprojects, I'll just use a global string and global error number like youdescribed.

Since it's all encapsulated into the module, I can always upgrade it to amessage file later if I want to.