Re: Procedure pointers - can I do this??

["Larry Ducie" <larry_ducie@xxxxxxxxxxx>]

Hi Simon,

<snip>
Not true. You can't get protected semantics but you can simulate package 
behaviour.

Specifying EXPORT will always export the variable or procedure from the 
module but it is only available to other modules that directly bind to it. 
If the module containing EXPORT is bound into a service program then EXPORT 
means it is a candidate for export. Whether it is visible by consumers of 
the service program depends on the the setting of EXPORT on CRTSRVPGM. If 
you use EXPORT(*ALL)--really dumb for reasons explained in the 
archives--then any candidate export will be visible. If you use binding 
source then you can omit the candidate variable or function from the public 
interface. It will still be available to other modules bound directly into 
the service program but will not be accessible by consumers of the service 
program.
</snip>

The problem with simulating "package behaviour" is that the "package" is a 
single program object. What I would like for Christmas is to be able to 
allow only selected (service) program object to be able to bind to selected 
exported procedures from another service program object.

For example, say I am writing a service program that uses several of my 
utility service programs and I want to access some data items within the 
utility service programs from within my service program.

Now, I could set the data items as exported - but that will only allow the 
data items to be imported by other modules within the same service program - 
as far as I'm aware it is not possible to export a data item outside a 
(service) program object. So my only alternative is to create getter methods 
to allow my service program access to the utililty service programs' data 
items. This would be my preferred approach to access data items.

Here's the rub - to export the getter method I would flag it as EXPORTable 
and compile the module. I'd then explicitly export the getter method from 
the service program object using binder language. BUT this is now available 
to ANY program that binds to the utility service program. There is no way 
(that I know of) that the utility service program can determine whether it 
should export or not.

This is pretty much what I meant by not having "package" access to data. To 
me the collection of bound service programs form the package.

Having said that, as we can only perform early binding, it isn't as much of 
an issue as it would be if we could perform late binding.

Cheers, and Happy Christmas

Larry Ducie