Makes perfect sense. Thanks for the information.
____________________________________
Gregory Schmidtberger
AVP - Consultant - Application Programming
Foreclosure & QC Technology
E-Mail gregory.schmidtberger@xxxxxxxxxxxxxxxxx
Blackberry 785-393-7297
Alternate 818-207-6194
____________________________________
-----Original Message-----
From: Scott Klement [mailto:rpg400-l@xxxxxxxxxxxxxxxx]
Sent: Thursday, March 15, 2012 1:22 PM
To: RPG programming on the IBM i / System i
Cc: Schmidtberger, Gregory P
Subject: Re: ILE Exporting Variables and *DUPVAR
Hi Gregory,
I believe *DUPVAR will give you whichever data structure is the *first* one it finds when binding.
You seem to be expecting that if you give the data structures the same name, they'll all be "the same structure", and therefore will be shared across all modules. This is not the case. They are all separate structures.
Personally, I do not like exporting variables (including data
structures) from modules. I consider this to be a bad practice, and if someone in my shop does it, I'll put a stop to it, and get very cranky with that programmer. Instead, I recommend calling procedures to set/retrieve values. That way, there's a well-defined interface to these parameters, and it's very easy to follow the chain of logic to access them.
But, if you wanted to solve this problem while still importing/exporting variables, the easiest solution would be to give a unique name to each module's data structure. Personally, I would prefix the data structure name with the module name, so you'd have:
MODULE1_structureName
MODULE2_structureName
etc
Not only does eliminate the ambiguity of the name, but it makes it crystal clear to whomever is reading your code which module's data they are referring to.
IMHO, anything exported from a module should be prefixed like this, including subprocedures. And, as mentioned above, I would prefer procedures instead of the data structures.
On 3/15/2012 12:58 PM, Schmidtberger, Gregory P wrote:
I have several modules compiled into a service program. They each
control inserts/updates/and deletes to specific tables. And all these
modules export a data structure with exactly the same name. Because
they all export a data structure with the same name I have compiled
the service program with *DUPVAR. This service program is like a
database service. And then I have an RPGLE program that binds to this
service program and uses the exported sub procedures from those
modules for database updates. This RPGLE program also IMPORTS the data
structure being exported by the modules. All are compiled and bound
correctly so it appears. When I tested this with a single module I was
able to get to the imported data in that data structure.
But I'm having a problem. Now that I have several modules compiled the
imported data structure is always coming back to the RPGLE program
empty. I would like to keep a single name for the exported data
structure so that my upstream programs can always
count on importing a single data structure. Does anyone know if what
I'm attempting to do should work or not? Or is the fact that all the
modules exporting the same data structure name is causing a problem?
Thanks.
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