auto_ptr vs shared_ptr

The main difference between std::auto_ptr and boost::shared_ptr is that
auto_ptr has the transfer-of-ownership semantic. That makes it impossible
to store auto_ptrs in STL containers because the containers use the copy
constructor when you store or get an element.

So, is it recommended to use shared_ptr instead? Are there any
disadvantages of shared_ptr? Is shared_ptr slower maybe?

It seems for shared_ptr you only need the boost headers, not the libraries.
Is that true?

Thanks!

re: auto_ptr vs shared_ptr

Markus Dehmann wrote:[color=blue]
>
> So, is it recommended to use shared_ptr instead? Are there any
> disadvantages of shared_ptr? Is shared_ptr slower maybe?
>[/color]

shared_ptr allocates a control block from the heap.
[color=blue]
> It seems for shared_ptr you only need the boost headers, not the libraries.
> Is that true?
>[/color]

Ask on the boost reflector.

--

Pete Becker
Dinkumware, Ltd. (http://www.dinkumware.com)

re: auto_ptr vs shared_ptr

Markus Dehmann wrote:[color=blue]
> So, is it recommended to use shared_ptr instead? Are there any
> disadvantages of shared_ptr? Is shared_ptr slower maybe?[/color]

Better don't waste your precious time and join the International Smart
Pointer Haters Club, an ever growing conglomerate of people who think
that smart pointers are not at all a smart idea. See e.g.
http://groups-beta.google.com/group/...6742e2b0036832

re: auto_ptr vs shared_ptr

Markus Dehmann schreef:[color=blue]
> The main difference between std::auto_ptr and boost::shared_ptr is that
> auto_ptr has the transfer-of-ownership semantic. That makes it impossible
> to store auto_ptrs in STL containers because the containers use the copy
> constructor when you store or get an element.
>
> So, is it recommended to use shared_ptr instead? Are there any
> disadvantages of shared_ptr? Is shared_ptr slower maybe?[/color]

Disadvantages? Sure, the share count had to be stored somewhere.
sizeof(auto_ptr<T>)==sizeof(T*) on many systems. Furthermore, this
may decrease the cache efficiency.

Furthermore, if the semantics you need /are/ transfer of ownership
(source/sink functions) then std::auto_ptr makes it clear what happens.

[color=blue]
> It seems for shared_ptr you only need the boost headers, not the libraries.
> Is that true?[/color]

AFAIK, yes, but that's technically off-topic (and it could change).

Regards,
Michiel Salters