[fpc-pascal] Question about System.Move()

[Bart]

On Sat, Jan 9, 2021 at 5:12 PM Yuriy Sydorov via fpc-pascal
<fpc-pascal at lists.freepascal.org> wrote:

> > 2. Is it OK if the elements of the array are (or contain) managed types?
>
> You need to manually finalize/free elements which are overwritten before calling Move.
So, if I move Arr[3] to Arr[1], I first have to finilize/free Arr[1].
After that move the bytes in Arr[3] are exactly the same as in Arr[1]
(by definition of how move works) AFAIU.
Is that a problem with refcounts, because they would be the same also
but the number of copies increased?

> Also if you intend to use Move for duplication of elements of managed types, it is better to use for-loop to copy each
> element separately to allow proper increments of references.
>
> > 3. Are there caveats if T is a specialization of a generic type definition?
>

Thanks for explaning.
OK, since this is a generic class, Systme.Move() can be safe, but it
is not guaranteed (almost by definition you never know what <T> is
going to be in the specialization.
So, I'll use a for loop to copy the data.

I assume that doing Arr[Index] := Default(T) will also finalize the
element if that element ismanaged?

-- 
Bart