Boost logo

Boost :

From: David Maisonave (boost_at_[hidden])
Date: 2006-01-31 05:09:17

"David Abrahams" <dave_at_[hidden]> wrote in message
> "David Maisonave" <dmaisonave_at_[hidden]> writes:

> >> IIUC, the thread-safety problem with reference-linked
> >> implementation
> >> isn't that so much that it's hard to achieve -- anyone can use a
> >> shared mutex -- it's that it's hard to make a thread-safe
> >> implementation efficient. That is to say, you pay for the cost of
> >> locking and unlocking a mutex, and there's no way around it (**).
> >> Locking and unlocking mutexes is way more expensive than performing
> >> the lock-free operations used by boost::shared_ptr.
> >
> > That's true. But it's been my experience that the majority of
> > development don't have objects access via multiplethreads or don't
> > run in a multithread environment. In this environment, you're paying
> > additional price for using boost::shared_ptr reference-count logic,
> > but not getting any benefits from it.
> Not if you're compiling without mt support on; the thread safety
> features of shared_ptr just compile away (and I think there's a macro
> you can use to force them off). Let's compare apples to apples: your
> reflinked implementation will be slower in a MT environment. I'm not
> yet convinced it will be faster in a ST environment unless you leave
> the MT features of shared_ptr turned on.

Currently, my test results don't support your above comment.
Please provide the this macro you're referring to.
Without this macro, there's no way of testing your claim.

Boost list run by bdawes at, gregod at, cpdaniel at, john at