> On Jun 19, 2019, at 10:21 AM, Ben Grasset <[email protected]> wrote:
>
> Is there any real purpose to implementing `Copy` versus just implementing
> `operator :=` (or `operator Implicit` when in {$mode Delphi})? Those can be
> inlined, and in practice are used in essentially all the places `Copy` is. By
> which I mean, IIRC you never really see calls to `fpc_copy_proc` in the
> generated assembler unless you've specifically implemented `Copy` yourself.
>
Copy operator is also called with dynamic arrays/open arrays. For example in
the code below the copy operator will be called for each of the 3 records. This
is why we need a Move operator because if TMyRec.Create allocates memory and
then is passed directly to the array we will need to perform another copy when
a simple swap would be sufficient (because the records are allocated in
temporary memory).
a := [TMyRec.Create(1),TMyRec.Create(1),TMyRec.Create(1)];
Regards,
Ryan Joseph
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