Re: Alternative COBOL "telco" source program

From: Robert Wagner (robert.deletethis_at_wagner.net)
Date: 05/31/04 

Date: Mon, 31 May 2004 19:14:47 GMT

LX-i <lxi0007@netscape.net> wrote:

>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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