* ctick:
Are there any advantages of using boost::shared_ptr 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_ptr 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_ptr.
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_ptr 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_ptr is not required.
--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?
