Re: Alternative COBOL "telco" source program

From: LX-i (lxi0007_at_netscape.net)
Date: 05/31/04 

Date: Sun, 30 May 2004 19:42:03 -0500

Robert Wagner wrote:
> LX-i <lxi0007@netscape.net> wrote:
>
>
>>when I
>>discovered that I could put a value clause on a group item, it changed
>>the way I defined tables (and other 01-level items). With my compiler,
>>there is a caveat (not sure if it's standard-imposed or not) - you can't
>>use a usage clause under a group level item with a value clause. So,
>>for my bit-switches, I can't say...
>>
>>01 MySwitches value zeroes.
>> 12 pic 1 binary-1.
>>
>>...which kind of stinks, but I can understand the limitation as well.
>
>
> Group names are implicitly pic x. It's an error to initialize bit/binary/packed
> variables with F0 (EBCDIC) or 30 (ASCII). It's common for compilers to disallow
> that value while permitting 'move zeroes to MySwitches'. Go figure.

It disallows any usage clauses. (I haven't tried "Display" - it may let
that one slide...)

> I use Value only to initialize constants i.e. fields that will never change.
> With regular variables, there are at least two potential bugtraps. One is the
> Initialize verb which, according to the '85 Standard, does not use your Values.
> The other is the operating system or Cobol runtime handling of called programs.
> If the caller does a Cancel, Values will be there on the next Call. But if the
> caller forgets or abends or someone else calls your .dll, they probably won't
> be.

Right. It would have been nice if the Initialize verb grabbed your
initial values, instead of just spaces/zeroes. Didn't I read that
that's an option in the 2002 standard? I've recently run into this
issue, as I'm taking programs that were once-through guys, and made them
loop endlessly (until the OS tells them to get lost). You find all
kinds of interesting stuff - variables not initialized, cursors not
closed properly, etc. :)

> A third, less common, problem is Local-Storage. As discussed here, Micro Focus
> used to leave it uninitialized. It didn't issue a warning about Value clauses,
> as it would in Linkage-Section, it just didn't use them. That's now fixed, but
> there's a chance the shop's production compiler is older than its development
> version, or another shop is using an old one.

I have yet to use a compiler that has Local-Storage... I'll file this
in my head for future reference.

> FWIW, 'pic 1' seems like sufficient information for the compiler to define one
> bit. It is on the AS/400. If your compiler makes you also write 'binary-1', that
> seems redundant.

I think it's required to flag it as an extension to the standard.
There's a compiler option that says you don't have to have that there
(and we use it), but it clutters up the print listings with extra
remarks, so I try to use it. As far as their rationale for requiring a
usage clause on Pic 1's... ? (Maybe if I end up working for Unisys one
day I can find out.) 

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