RE: Reason for allocating memory

["Joe Lee" <LeeJD@xxxxxx>]

I don't believe that will cause a problem since when the program ends
the 400 will clean up all the memory it was using. The deallocating of
the memory is more important while the program is running. For instance
in my program I am creating and destroying the data structures fairly
regularly, when I get rid of a data structure I need to be sure that all
the memory that was allocated for it is deallocated. Failure to
deallocate the memory probably wouldn't be a problem for a program that
only runs for a short period of time, but if the program runs for an
extended period, in my case it is a CGI service program that returns
with LR off and stays in memory as until  the web server job is ended,
then the memory leaks could become significant. Hans or Barbara could
probably give a more detailed answer about what happens when memory
isn't deallocated.




>>> justin@RELIATEK.COM 07/26/2002 10:22:32 >>>

>>> There are only twp problems with using allocated memory that I
see.
One
is that a large portion if not most RPG programmers are not familiar
with it. And if you use it you have to be careful to deallocate it
when
you are done with it.

What do I need to do if my programs errors out before the DEALLOC
statement? I just had this happen.


-----Original Message-----
From: rpg400-l-admin@midrange.com [mailto:rpg400-l-admin@midrange.com]

On Behalf Of Joe Lee
Sent: Friday, July 26, 2002 11:56 AM
To: rpg400-l@midrange.com
Subject: Re: Reason for allocating memory

Well, your scenario may not be as exaggerated as you think. I have a
program that has a dynamically allocated array of pointers to data
structures containing a "name" variable, a pointer to a null
terminated
string, and a couple of pointers to linked lists of data structures
containing pointers to null terminated strings.

A dynamically allocated array where the array has the potential to
have
a large number of elements or where the elements are very large is the
perfect example of when to use allocated memory.  Of course you can't
use LOOKUP with a dynamic array, but if you have an array large enough
to need dynamic allocation you probably don't want to use something as
slow as LOOKUP anyway.

There are only twp problems with using allocated memory that I see.
One
is that a large portion if not most RPG programmers are not familiar
with it. And if you use it you have to be careful to deallocate it
when
you are done with it.


Joe

>>> acassidy@pioneermetals.com 07/26/2002 09:20:04 >>>
Wait. If you have a much-used program, that uses an array, for
example,
say
len(5000) (to match, say a record format, yes, we've got 'em, you too
probably), and depending on selections this can go anywhere from zero
or one
to maybe a 2 thousand, go dim(2000), now you're using 10 meg of CPU.
Say
you're getting twenty users signed on at once. Wouldn't this be a
reason? Or
why not?

I know the scenario is an exaggerated stretch, but please humor me, as
I
remember thinking sometimes in a case like this I might want to
allocate
memory this way.. This is not to detract from the thrust of your
point,
which seems to be that they trying to duplicate C-functionality into
RPG.

Come to think of it, why is it in C?

--Alan




----- Original Message -----
From: "Justin Houchin" <justin@RELIATEK.COM>
To: <rpg400-l@midrange.com>
Sent: Friday, July 26, 2002 11:56 AM
Subject: RE: Reason for allocating memory


> So if I understood you correctly, allocating memory is related to
the
> "C" programming language?
>
> -----Original Message-----
> From: rpg400-l-admin@midrange.com
[mailto:rpg400-l-admin@midrange.com]
> On Behalf Of Jon Paris
> Sent: Friday, July 26, 2002 10:50 AM
> To: rpg400-l@midrange.com
> Subject: Reason for allocating memory
>
>  >> Could someone tell me the reason they would dynamically allocate
> memory.
>
> Because while at least trying to produce a working example in RPG,
the
> people who wrote it were completely clueless about the language and
> effectively translated C logic into RPG wherever they found a
matching
> function.
>
> I hate to say this because they are on of the few groups in the
whole
of
> IBM
> that realize that we don't all program in C but ....
>
> There is no reason why a regular RPG variable 256 long could not be
used
> instead of the method they used.  Same applies to a whole bunch of
other
> allocations and similar silliness.
>
> Jon Paris
> Partner400
>
>