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Re: ADL fails for friend functions...

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On 11/02/2011 03:28 PM, Werner wrote:
> On Nov 2, 3:40 pm, Edek<edek.pienkow...@gmail.com>  wrote:
>
> I've deliberately not defined the friend outside. The question
> still stands - can you call join in any other way than by
> removing Y's join from the overload set?

"Using" does not remove Y::join from overload set. It adds n1::join.

>
>> Could you quote directly, I am confused with what you wrote, it does not
>> fit anything I can come up with.
>
> Quote Modern C++ Design Ch 7.4:
>
> "However, experience has proven that member functions are not very
> suitable for smart pointers. The reason is that the interaction
> between member function calls for the smart pointer for the
> pointed-to object can be extremely confusing."

Ah, yes, I missed the simplest possible thing.

If my opinion matters at all, + has the same problem. You
"never know" if you are adding 1 to a pointer to int or
to the int-pointed-to. And if an Object has a parent Object,
you never know if it is the parent or the parent's parent.
Oh, well... I can live with that. Friend reset is imo worse,
can call a member of class where it is used by mistake,
or in a better case cause ambiguity, though VC sometimes
takes shortcuts here.

>
> I've noticed that in Loki he has, depending on compiler either
> defined the friends in the class or in the namespace...
>
> For this reason (ADL not kicking in automatically if overload
> exists) I'm beginning to think that this was boosts choice for using
> members instead of non-members in their smart pointers.

Don't know. Maybe you can dig mail archives for discussions.

For me personally, the consequence of what I wrote above is that
the programmer does have to keep track of what is a pointer and
what is not a pointer. While the -> instead of . does happen
in my case sometimes (when I change a ref to a ptr or the opposite)
I have never hit the described problem. I wonder only if
I become to hit this problem since I started using auto a lot.
Still, member seems more natural to me, I find it more readable.
Also note that reset(whatever) will match reset(T) if whatever is
convertible to T and there is no preferred alternative and
reset is not a member.

Edek

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Thread

ADL fails for friend functions... Werner <werasm@gmail.com> - 2011-11-02 06:23 -0700
  Re: ADL fails for friend functions... Edek <edek.pienkowski@gmail.com> - 2011-11-02 14:40 +0100
    Re: ADL fails for friend functions... Werner <werasm@gmail.com> - 2011-11-02 07:28 -0700
      Re: ADL fails for friend functions... Edek <edek.pienkowski@gmail.com> - 2011-11-02 16:08 +0100
      Re: ADL fails for friend functions... Victor Bazarov <v.bazarov@comcast.invalid> - 2011-11-02 12:34 -0400

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