Re: Variable length MODS

["Peter Dow" <pcdow@xxxxxxxxx>]

Hi James,

I believe the compiler puts in upper boundary checking based on what you
enter as the dimensions or occurrences of the array or data structure, i.e.
no relation  to the pointer. In the example I gave Tom, there's an array
with a DIM(9999).  If only enough memory is allocated for 3 array entries,
what happens when he references entry 4?  As far as the compiler is
concerned, 4 is well within the defined upper boundary of 9999, but in fact
no memory has been allocated for that entry and it moves into uncharted
territory, but does not (as far as I know) give an error.

Regards,
Peter Dow
Dow Software Services, Inc.
909 425-0194 voice
909 425-0196 fax

----- Original Message -----
From: "James David Rich" <james@eaerich.com>
To: <RPG400-L@midrange.com>
Sent: Friday, April 13, 2001 3:01 PM
Subject: Re: Variable length MODS


> On Fri, 13 Apr 2001, Peter Dow wrote:
>
> > Hi Tom,
> >
> > As far as I know, you'd get weird data, with no array bounds error,
> > because as far as the compiler knows, the upper array boundary (in my
> > example) is 9999. In other words, yes, you have to be careful how you
> > use it, and check the NumLabels or whatever instead of the %elem(array)
> > test.
>
> If a pointer is used shouldn't there be *no* upper boundary? Just alloc
> and it keeps growing.
>
> James Rich
> james@eaerich.com
>
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