Re: [Boost-users] [shared_ptr] deleter that destroys shared_ptr -is it safe?

Subject: Re: [Boost-users] [shared_ptr] deleter that destroys shared_ptr -is it safe?
From: Peter Dimov (pdimov_at_[hidden])
Date: 2009-09-09 04:15:55

Stefan Strasser wrote:
> Am Tuesday 08 September 2009 23:28:21 schrieb Igor R:
>> Hello,
>>
>> Is the following code legal and safe -
>> a) according to the shared_ptr specs
>> b) with the current boost::shared_ptr implementation
>>
>
> it is, because shared_ptr::reset() is specified to be equivalent to
> shared_ptr().swap(*this).
> so the contents of a::p_ are first swap()ed to a temporary and then p
> is deleted when the temporary goes out of scope, with a::p_ being
> empty.
>
> however, be careful that you leave it at reset() and don't change it
> to an assignment.
> p_=shared_ptr<a>(); is NOT safe and is not equivalent to p_.reset()
> in this case.
> the assignment in fact produces a invalid write with the current
> implementation.

This was fixed in 1.39, if I'm not mistaken (see revision 51643). Are you 
sure that it fails with the current implementation?