Re: const shared_ptr<> oops

From: John Harris (john.harris_at_[hidden])
Date: 2003-05-01 09:35:53

--- In Boost-Users_at_[hidden], Darin Adler <darin_at_b...> wrote:
> On Thursday, May 1, 2003, at 04:57 AM, Hossein Haeri wrote:
> 
> > So the true answer is not to forget to call the reset() member 
> > function for every shared_ptr<>, before the end of it's scope.
> 
> No, that won't do any good. When you do a reset(), the shared_ptr 
> relinquishes ownership of the thing it points to. If it's the sole 
> owner, it will destroy the object. It's simply an error to put a 
> pointer to a stack object inside a shared_ptr; you can't correct 
that 
> error with a reset() call.
> 
>      -- Darin

I agree with Darin.  Shared_ptr is used for automatically deleting a 
heap object when the last reference to it (that is, the last copy of 
the shared_ptr managing it) goes out of scope.  It keeps count as the 
shared_ptr is copied around through parameters and return values and 
is constructed and destroyed.  The underlying count goes up on 
construction and down on destruction.  When the count gets to 
zero, 'delete' is called on your object.

It is used to prevent copies of an object from being made.

Hossein, if you'll post a description of what you really want to do, 
then we might be able to suggest a better idiom for you to follow.

jh