Re: Containers - nontrivial element access

[Maciej Sobczak <see.my.homepage@gmail.com>]

On 3 Pa , 21:15, Simon Wright <simon.j.wri...@mac.com> wrote:

> I'm no expert, but I would have expected C++ to distinguish given
>
>    struct Foo {
>       ...
>    };
>
> the three different functions
>
>    Foo return_by_value();
>    Foo* return_by_access();
>    Foo& return_by_reference();

Yes, it does distinguish them.
Note that first and third version are not distinguishable in syntax at
the call-site (except that only the third one allows to bind to non-
const references).

> I wonder what the difference between Foo* and Foo& is? I don't suppose
> there's any difference at the object code level? (except Foo* can be
> 0).

Foo* can be NULL, and there is no provision for anything at the object
code level.
Actually, this "level" is not relevant at all as far as the language
is concerned.

But in practical terms (standard aside), you can expect that Foo* and
Foo& will not differ at the object level, although things can get more
interesting when the calls are inlined.

--
Maciej Sobczak * www.msobczak.com * www.inspirel.com