Re: [boost] Proposal to add smart_ptr to the boost library

From: Sam Partington (sam.partington_at_[hidden])
Date: 2006-01-30 11:02:06

> You can avoid having to make the implementation thread safe by making the
> pointee thread safe.
> This can be done by using an intrusive lock.

How?  The FAQ is talking about making the reference count thread safe,
not the object thread safe.

class A { };

void f(ptr<A> a)  {  }

int main()
{
        ptr<A>  a(new A);
        boost::thread t(boost::bind(f, a));
}

Which thread does the deallocation of a?  What protects both of them
from trying to deallocate it at the same time?

> I guess this could be considered not enough of an advantage if 22% to 30%
> extra efficiency is not that important.
> But some developers would differ.

Until there is a thread safe implemenation then any performance
comparisons are irrelevant because you're comparing apples and
oranges.

Sam