boost::shared_p tr vs. auto_ptr

[ctick]

Are there any advantages of using boost::shared_p tr other than auto_ptr from
standard library?

[Alf P. Steinbach]

* ctick:

Are there any advantages of using boost::shared_p tr other than auto_ptr from
standard library?

There are a number of advantages.

First, they're two different beasts: std::auto_ptr transfers ownership
so that with some caution you can guarantee that only one pointer points
to a particular object at any time, whereas boost::shared_p tr provides
reference counting so that many pointers can point to the same object.

Second, you cannot put std::auto_ptr's in a standard container, but you
can with boost::shared_p tr.

Third, although the standard specially provides for calling a destructor
on an object of incomplete class, not all compilers support that. This
problem pops up in e.g. the pimpl idiom. With boost::shared_p tr you
replace the direct delete expression in std::auto_ptr with a custom
destroy-function that can be defined where the full definition of the
class is available, side-stepping the issue.

I could list up a fourth and fifth advantage, and perhaps more, but I
think that's enough. The main advantage of std::auto_ptr is that it's
always there and that it's standard. It should therefore be used when
the generality of e.g. boost::shared_p tr is not required.

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[David Harmon]

On Sat, 19 Jun 2004 20:23:26 GMT in comp.lang.c++, al***@start.no (Alf
P. Steinbach) wrote,

I could list up a fourth and fifth advantage, and perhaps more, but I
think that's enough. The main advantage of std::auto_ptr is that it's
always there and that it's standard. It should therefore be used when
the generality of e.g. boost::shared_p tr is not required.

I think that auto_ptr also has less overhead cost than shared_ptr's
ownership tracking mechanism when you are doing the simple things it is
capable of and have no need for shared ownership.

[Siemel Naran]

"ctick" <ct***@flare.co m> wrote in message
news:g61Bc.6352 $OB3.4344@bgtns c05-

Are there any advantages of using boost::shared_p tr other than auto_ptr from standard library?

You're comparing apples to oranges.

[Julie]

Siemel Naran wrote:

"ctick" <ct***@flare.co m> wrote in message
news:g61Bc.6352 $OB3.4344@bgtns c05-

Are there any advantages of using boost::shared_p tr other than auto_ptr

from

standard library?

You're comparing apples to oranges.

http://www.people.virginia.edu/~rjh9u/apporang.html

[Richard Herring]

In message <40************ ****@news.west. earthlink.net>, David Harmon
<so****@netcom. com.invalid> writes

On Sat, 19 Jun 2004 20:23:26 GMT in comp.lang.c++, al***@start.no (Alf
P. Steinbach) wrote,

I could list up a fourth and fifth advantage, and perhaps more, but I
think that's enough. The main advantage of std::auto_ptr is that it's
always there and that it's standard. It should therefore be used when
the generality of e.g. boost::shared_p tr is not required.

I think that auto_ptr also has less overhead cost than shared_ptr's
ownership tracking mechanism when you are doing the simple things it is
capable of and have no need for shared ownership.

For the _really_ simple things, consider boost::scoped_p tr. No
overheads, no sharing or transfer of ownership at all.

--
Richard Herring