Re: Long Constant Names

[Barbara Morris <bmorris@xxxxxxxxxx>]

Jon Paris wrote:
> 
>  >> Wouldn't an exported constant Variable have other attributes such as
> type, length, etc?
> 
> Unless I'm mismembering, exported variables don't really have any attributes
> other than a name.  It is up to the programmer to make sure the storage is
> mapped in the same way in the importer as it was in the exporter.
> 
> According to the ILE Concepts manual, the length of strong exports has to be
> known at compile time.  However, although RPG uses the strong export model,
> I see no evidence that length has any effect.  A test module that exported a
> 30 character field was successfully imported into other modules as both a 20
> and as a 40 character field with no problems.
> 
> It seems likely that exports like parms are "just a pointer" with no other
> special attributes.
> 

I think (but don't know) that the actual storage is part of the
exporting module's static storage; the length of that would have to be
known at compile time.  But indeed the length doesn't seem to be stored
as part of the export/import information for the module.

But export/import variables have attributes such as type and length in
exactly the same way that parameters passed by reference to.  The system
knows nothing about the type and length; only the compiler knows.  Of
course, the compiler only knows what the programmer tells it; similar to
only having prototypes coded in one place, you should only have
import/export variables coded in one place (/copy file) too.

D globalVar           s          10a
 /if defined(main)
D                                     export inz('abc')
 /else
D                                     import
D                                     ?const?
 /endif