Re: Memory allocation strategy

The only linked list, I've done was in C. There each List Element would
have 2 pointers, one pointer the Prior List Element, and one pointer to the
Next List Element.

If we moved a List Element, we had to change the pointers in both Adjacent
List Elements. But no pointer changes were required in the Moved List
Element itself.


-------- Original Message --------

From: "Rory Hewitt" <rory.hewitt@xxxxxxxxx>
Sent: Sunday, January 09, 2011 12:36 AM
To: "RPG programming on the IBM i / System i" <rpg400-l@xxxxxxxxxxxx>
Subject: Re: Memory allocation strategy

Ooh, good point, I hadn't thought of that... My linked list stuff uses
offsets rather than pointers, so it works either way...


On Jan 8, 2011 7:53 PM, "Elbert Cook" <elbert@xxxxxxxxxxxxxxx> wrote:

If you allocate 100 bytes of memory and for some reason, there is a

pointer

within those 100 bytes that points to a subset of itself.

Now you realloc to 200 bytes and the 100 bytes gets move to a

different

memory range.

Then the embedded pointer would still retain its original value and no
longer point to a subset of itself at the new location.

Lets not ask the question why someone would do that.


-------- Original Message --------

From: "Rory Hewitt" <rory.hewitt@xxxxxxxxx>
Sent: Saturday, January 08, 2011 8:45 PM
To: "RPG programming on the IBM i / System i" <rpg400-l@xxxxxxxxxxxx>
Subject: Re: Memory allocation strategy

Indeed, pointers in user-allocated memory are always retained, as far

as

I

know, even through multiple reallocations. If that weren't the case,

all

my

apps would fail...

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