[2 days left] What’s wrong with your cloud strategy? Learn why multicloud solutions matter with Nimble Storage.Register Now

x
?
Solved

SetLength and pointers

Posted on 2003-10-30
4
Medium Priority
?
368 Views
Last Modified: 2012-05-04
I'll try and confuse everyone as little as possible here.

I have a record. It is called email_info. This record is basically an e-mail account.
I have email_accounts which is an array of email_info.

I add new accounts to a list (similar to a treeview i guess.) when the user mouses over, they see a tooltip (hint) containting data from that account. i.e. new messages, etc..

Problem. When I add a new record (account) I call SetLength(email_accounts, Length(email_accounts) +1)

this moves my array to a different location in memory. so when i add a new account, the accounts above it don't know where to grab their data. so i usually get some funky stuff in there.

what would solve this? a pointer to the pointer that's already in the tooltip?

this is probably VERY confusing, sorry :)
0
Comment
Question by:gwarguitar
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
4 Comments
 
LVL 2

Accepted Solution

by:
j42 earned 225 total points
ID: 9656238
I can see two ways:

1. Don't store the address of your record but the index in the array instead
2. Don't use records at all. Define a class to store your email info and
   use a TObjectList as container.
0
 
LVL 5

Expert Comment

by:DeerBear
ID: 9656314
Hi,

I basically second j42 here, but I would add some insight on the matter.

First of all, we've no clue of the record structure( yes, it matters ) and I
think you're using LongStrings in it, right? <g>

If I was you, in order to have a safe move, I'd do this:

procedure ExpandEmailArray( SrcArr : array of TEmailInfo;Delta : Integer;var DstArr : array of TEmailInfo );

var SrcLen : Integer;
      Elem_Idx : Integer;
begin
   SrcLen := Length( SrcArr );
   SetLengthDstArr( DstArr,Delta );
   for Elem_Idx := 0 to Pred( SrcLen ) do
   begin
      DstArr[ Elem_Idx ] := SrcArr[ Elem_Idx ];
   end;
end;

Anyway, an OO approach would definitely better.

HTH,

Andrew
0
 

Author Comment

by:gwarguitar
ID: 9679659
1. Don't store the address of your record but the index in the array instead

that put me on the right track, thanks, guys.
0
 
LVL 2

Expert Comment

by:j42
ID: 9679759
You're welcome.
0

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction The parallel port is a very commonly known port, it was widely used to connect a printer to the PC, if you look at the back of your computer, for those who don't have newer computers, there will be a port with 25 pins and a small print…
Introduction Raise your hands if you were as upset with FireMonkey as I was when I discovered that there was no TListview.  I use TListView in almost all of my applications I've written, and I was not going to compromise by resorting to TStringGrid…
In this video you will find out how to export Office 365 mailboxes using the built in eDiscovery tool. Bear in mind that although this method might be useful in some cases, using PST files as Office 365 backup is troublesome in a long run (more on t…
In response to a need for security and privacy, and to continue fostering an environment members can turn to for support, solutions, and education, Experts Exchange has created anonymous question capabilities. This new feature is available to our Pr…
Suggested Courses

656 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question