Re: [boost] [Thread] possible bug in Move emulation "portable interface"

Subject: Re: [boost] [Thread] possible bug in Move emulation "portable interface"
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2013-09-07 04:11:16

Le 07/09/13 10:00, Vicente J. Botet Escriba a écrit :
> Le 04/09/13 07:53, Gavin Lambert a écrit :
>> I tried submitting this via Trac but for some reason it was convinced 
>> that my bug report contained spam, while refusing to tell me what 
>> part it was objecting to, and also refusing to give me a captcha or 
>> anything to convince it otherwise.
>>
>> Anyways:
>>
>> Bug 1: the Boost.Thread documentation and release history indicate 
>> that BOOST_THREAD_VERSION==3 is the default since v1.52. As far as I 
>> can tell this has never been true in any released version; the latest 
>> code still has ==2. (I found a thread in boost-devel that was 
>> debating consequences of making breaking changes by default, which I 
>> assume is why this change was not actually made; but the docs need 
>> correcting.)
> This was my intention, but this was not possible as the Boost 
> community didn't accept the breaking changes.
> Please could you point me where in the documentation this 
> misinformation is still there?
>>
>> Bug 2: when writing code using the Boost.Thread "Portable Interface" 
>> for move support/emulation, it recommends using the 
>> BOOST_THREAD_DCL_MOVABLE_BEG macro to "avoid conflicts with 
>> Boost.Move". However regardless of C++11 or not or the 
>> BOOST_THREAD_VERSION it defines a template specialisation in a way 
>> that assumes that it is called only from "namespace boost". 
> You are right. The macro must be used inside the boost namesapce.
>> As this usage is unlikely for any code outside the boost library 
>> itself, I think this is a bug.
> Well, as the constraint is not on the documentation, I consider it a bug.
>>
>> namespace user
>> {
>> template<typename T>
>> class test
>> {
>> public:
>> BOOST_THREAD_COPYABLE_AND_MOVABLE(test)
>>
>> test() {}
>> test(const test&) {}
>> test& operator=(BOOST_COPY_ASSIGN_REF(test) o) { return *this; }
>> test(BOOST_THREAD_RV_REF(test) o) {}
>> test& operator=(BOOST_THREAD_RV_REF(test) o) { return *this; }
>> };
>> BOOST_THREAD_DCL_MOVABLE_BEG(T) test<T> BOOST_THREAD_DCL_MOVABLE_END }
>>
>> The above code will not compile. It does compile if the DCL define is 
>> moved into a "namespace boost" block, but I do not regard this as an 
>> acceptable solution.
>>
>> Suggested fix is to explicitly specify the namespace in the macro, 
>> eg. replace "enable_move_utility_emulation" with 
>> "::boost::enable_move_utility_emulation".
>>
>>
>>
> Humm, I don't know if this is correct. In any case I didn't know that 
> we could specialize templates this way. Could some one confirm this 
> kind of specializations is portable?
>
>
If I do the change I get the following error:

../../../boost/thread/lock_types.hpp:500:58: erreur: global 
qualification of class name is invalid before ‘{’ token

I suspect that you would need to make the specialization inside boost 
namespace. I will update the documentation.

Best,
Vicente