Re: [boost] [utility]result_of - erroneous result type from a C++11 lambda

Subject: Re: [boost] [utility]result_of - erroneous result type from a C++11 lambda
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2013-04-02 16:57:44

Le 02/04/13 20:46, Vicente J. Botet Escriba a écrit :
> Le 02/04/13 19:42, Evgeny Panasyuk a écrit :
>> 02.04.2013 21:16, Vicente J. Botet Escriba:
>>
>>> Is this a know bug on boost::result_of or gcc compiler?
>>
>> Try http://liveworkspace.org/code/J6bEg$0 :
>>
>> #define BOOST_THREAD_PROVIDES_FUTURE
>> #define BOOST_RESULT_OF_USE_DECLTYPE
>> #include <boost/thread.hpp>
>>
>> int main()
>> {
>>    boost::future<int> f1 =
>>       boost::async( []() -> int {return 123;} );
>> }
>> // ___________________________ //
>>
>> For additional info refer 
>> http://www.boost.org/users/news/a_special_note_for_boost_1_52_0_and_higher.html 
>> , 
>> http://www.boost.org/doc/libs/1_53_0/libs/utility/utility.htm#result_of
>>
> Thanks, this works.
>
> Should then the user of Boost.Thread define 
> BOOST_RESULT_OF_USE_DECLTYPE explicitly?
>
>
BTW,

the definition of BOOST_RESULT_OF_USE_DECLTYPE can be done only if 
BOOST_NO_CXX11_DECLTYPE because otherwise the inclusion of of 
result_of.hpp generates some compiler errors on compilers not supporting 
decltype.

#include <boost/config.hpp>
#if ! defined  BOOST_NO_CXX11_DECLTYPE
#define BOOST_RESULT_OF_USE_DECLTYPE
#endif
#include <boost/thread/future.hpp>

Could result_of.hpp undefine BOOST_RESULT_OF_USE_DECLTYPE if 
BOOST_NO_CXX11_DECLTYPE is defined?

Vicente