Re: [Boost-users] how to delete references to objects from a container...

Subject: Re: [Boost-users] how to delete references to objects from a container...
From: Jeff Flinn (TriumphSprint2000_at_[hidden])
Date: 2009-12-09 11:26:06

rv_nath wrote:
> Dear Jeff, 
> Thanx for your quick reply.  FUrther to the same question, 
> can you please explain:
>    > There is also weak_ptr originally intended to break cycles which may be
> of use to you.
>   - the meaning of breaking cycles, and how it can help in this situation.
> 
> It is said that a weak ptr doesn't increment the refcount.  That means there
> is a possibility of the pointee object being deleted, while a weak ptr is
> holding a reference of it.  So, in my understanding, if i return a weak-ptr
> to the clients of my object, then I will be able to delete my object at time
> of my choosing inspite of how many number of weak-ptr references the clients
> may have. But after this, the weak-ptr reference becomes invalid. Am I
> right?

(please don't top post)

Yes, that's right.

See:

  http://www.boost.org/doc/libs/1_41_0/libs/smart_ptr/weak_ptr.htm

You'd have to lock the weak_ptr to access a shared_ptr to the resource, 
which would litter your code with a lot of conditionals to check to see 
if the shared_ptr is not null. While this may be a valid design approach 
in some cases, my first inclination would be to redesign taking into 
account the true nature of the relationships your dealing with, IMHO of 
course.

Jeff