Re: [Boost-users] Is weak_ptr lock method thread safe?

Subject: Re: [Boost-users] Is weak_ptr lock method thread safe?
From: Slava (Viatcheslav.Sysoltsev_at_[hidden])
Date: 2013-04-25 05:36:04

On Wed, 24 Apr 2013 18:30:13 +0200, Gottlob Frege <gottlobfrege_at_[hidden]>  
wrote:

> On Mon, Apr 22, 2013 at 4:26 AM, Andrea Galeazzi <galeazzi_at_[hidden]>  
> wrote:
>
>>  I googled this question but, although there are many discussions about
>> it, I didn't find a clear answer.
>> Can I assume the following piece of code to be thread safe?
>>
>> shared_ptr<T> p1(new XXX); //Main threadweak_ptr<T> wp(sp); //Main  
>> thread
>>
>> //Then I run two threads: A and B
>> p1.reset(); // thread A
>> shared_ptr<T> p2 = wp.lock(); // thread B
>>
>> In other words, is lock method atomic in respect to deference of the
>> shared point?
>>
>>
>>
< snip>
>
> What you are doing is thread-safe.  It is part of the docs, can be seen  
> in
> the implementation (although it is hard to see), and tons of code would
> break if it wasn't.
>
> Tony

Ok, after thorough debugging session today I backup the statement above.  
Your specific use-case is thread-safe, at least with boost 1.53 on x86  
architecture.

-- Slava