Re: [boost] [asio] Tutorial 7 using strdup, new

From: Felipe Magno de Almeida (felipe.m.almeida_at_[hidden])
Date: 2006-02-06 19:00:29

On 2/6/06, Giovanni P. Deretta <gpderetta_at_[hidden]> wrote:

[snip]

> While Christopher can certainly answer better than i can, i think that
> the answer is: because it often doesn't need to be! A socket is a non
> copyable value based object. It doesn't need dynamic allocation and
> could very well be stack based (as the datagram_socket and the
> socket_acceptor in the example).

And it doesnt have to, I use shared_ptr to handle my sockets while not
using dynamic allocation. The ability to configure a deleter makes it
very easy to handle resources without using operator new and nor
delete.
And IMO it would be much easier than prohibing copying of the socket.

>
> Only if you need the lifetime of the object to be dynamic (as the
> example does, but it is *not* always the case) you directly allocate it.
> Or make it be a member of a class that is itself dynamically allocated.

Even making it a member of the class you'll probably need it to be
passed along to another class, which is impossible without
copy-construction. Which would need the socket (or the class that owns
the socket) to be dynamically allocated and its lifetime to be watched
(maybe through shared_ptr).

>
> You could make the socket class hold internally a shared_ptr to a
> socket_impl and make it (shallow) copyable, but it would it be
> surprising and would require dynamic allocation(*) even if not needed.

Yes, probably always since you cant copy or move the socket...

>
> A nice solution would be to make socket movable...

IMO, it wouldnt be a complete solution, but part of it.

>
> (*) Not really, all copies of stream could hold a copy of socket_imp
> and only the last one would close it, but it would still require some
> sort of reference counting.

shared_ptr can be used, since it is already done and optimized to a
lot of platforms. Why not use it inside the library?

> --
> Giovanni P. Deretta
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--
Felipe Magno de Almeida