Re: [boost] [config] clang deleted functions bugged

Subject: Re: [boost] [config] clang deleted functions bugged
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2013-10-27 22:23:04

Le 28/10/13 02:54, Jonathan Wakely a écrit :
> On 28 October 2013 01:45, Jonathan Wakely wrote:
>> On 28 October 2013 00:12, Vicente J. Botet Escriba wrote:
>>> Boost.Thread defines a private constructor when
>>> BOOST_NO_CXX11_DELETED_FUNCTIONS is defined and in this case there is no
>>> compiler error.
>> That might be true, but that is not sufficient to conclude that clang
>> doesn't support deleted functions!
>>
>> The stackoverflow question you linked to is years old and Howard's
>> answer is wrong (but Johannes's comments on that answer are correct,
>> and agree with what Peter already said.)
>>
>> The stack trace shows that std::vector is trying to copy the element,
>> not move it.
>>
>> My guess would be that boost::thread's move constructor is not
>> noexcept, so the libc++ std::vector refuses to use a move when
>> inserting, and falls back to a copy instead, which fails. That is the
>> correct, standard behaviour for std::vector. If my guess is correct
>> you should make the move constructor noexcept.
> Yep, here's your bug:
>
>          thread(BOOST_THREAD_RV_REF(thread) x)
>          {
>              thread_info=BOOST_THREAD_RV(x).thread_info;
>              BOOST_THREAD_RV(x).thread_info.reset();
>          }
>
> That is missing a BOOST_NOEXCEPT exception-specification.
You are right, I missed it. And adding it fixes the issue I had. Thanks 
so much.
My apologies for the noise. Hopping others have learn something from you 
insight.
> Why not simply do x.thread_info.swap(thread_info) to avoid ref-count
> updates in that constructor?
I will change it.
>
> Also, there's a bogus copyright date in boost/thread/detail/thread.hpp:
>
> // (C) Copyright 20011-2012 Vicente J. Botet Escriba
>
>
Thanks for catching this ;-)
Vicente