[fpc-pascal] How to work with reference-counted strings in dynamically created objects

[Howard Page-Clark]

On 28/03/2015 08:31, Sven Barth wrote:
> Am 28.03.2015 06:51 schrieb "Howard Page-Clark" <hdpc at talktalk.net
> <mailto:hdpc at talktalk.net>>:
>  >
>  > The following program, compiles and runs as expected using a
> shortstring declaration in the TExample record.
>  > Could someone explain how to adapt it to cope with a TExample record
> containing ansistrings?
>
> [snip]
>  > procedure TExampleList.Initialize(aCount: integer);
>  > var
>  >   i: integer;
>  >   pex: PExample;
>  > begin
>  >   for i:=1 to aCount do begin
>  >     GetMem(pex, SizeOf(TExample));
> // use New(pex) instead of GetMem(...)
>  >     pex^.Init(Format('Example#%d, Value=%d',[i, Random(100)]));
>  >     FList.Add(pex);
>  >   end;
>  > end;
>  >
> [snip]
>
>  >
>  > destructor TExampleList.Destroy;
>  > var
>  >   i: integer;
>  > begin
>  >   for i:=0 to FList.Count-1 do
>  >     Freemem(FList[i], SizeOf(TExample));
> // Use Dispose(PExample(FList[i])) instead of FreeMem(...)
>  >   FList.Free;
>  >   inherited Destroy;
>  > end;
>  >
>
> It's best to always use New/Dispose if you work with records. Use
> GetMem/FreeMem only if you work with unstructured memory areas or where
> you don't really know the real size beforehand.
>
> Regards,
> Sven
>
Thank you

Howard

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