Le 03/05/12 11:15, loic.actarus.joly@numericable.fr a écrit :
---- Message d'origine ---- >De : "Robert Ramey"<ramey@rrsd.com> >À : boost@lists.boost.org >Objet : Re: [boost] question about C++11 guidelines >Date : 03/05/2012 08:30:06 CEST > >Eric Niebler wrote: > > Say I'm rewriting an existing Boost library and targeting C++11 > > users. I plan to ship C++03 and C++11 versions of my library > > side-by-side, so back-compat isn't an issue for the new code. Is > > there a reason to prefer using Boost's versions of utilities like > > enable_if, type traits, integral constant wrappers (e.g. mpl::int_), > > tuples, etc., over the now-standard ones? > > > > I'm leaning toward using std:: where I can, and falling back on > > Boost's versions only when there is a compelling reason. > > Isn't easier to just use the boost versions knowing that they > will be implemented in the most efficient/appropriate way > for the compiler in question? > From what I understood, std::make_shared is more efficiently implemented on some platforms that boost::make_shared, so I would not assume that boost version is better than the version provided by the compiler. From a boost user point of view, I have another issue with boost compatibility with C++11, that is not used by either proposal: - If types such as boost::shared_ptr and boost::tuple are used in the library boost.sampleLib, whenever I want to interface boost.sampleLib with other code that was written without boost, and makes use of std::shared_ptr or std::tuple, I have troubles, and need to convert/copy objects
Yes, this is an issue that merits a better solution.
- If types such as std::shared_ptr and std::tuple are used in the library boost.sampleLib, whenever I want to interface boost.sampleLib with other code that was written with boost, and makes use of boost::shared_ptr or boost::tuple, I have troubles, and need to convert/copy objects The more I think of it, the more I believe the right solution is not to have two different types, but making sure that on a platform where std::shared_ptr exists, boost::shared_ptr is defined as an alias to std::shared_ptr, and just the same for all C++11 types that were first developped with boost. Frankly, I have been using boost on VC10 that contains std::shared_ptr for quite some time now, and I can say it is quite a pain, there are many subtle compilation problems that all come down to the fact that there are duplicated types with the same name in the same program. For instance: struct A { A(int i); A(std::vector<int> const&v); }; using boost::make_shared; std::vector<int> v; boost::shared_ptr<A> p1 = make_shared<A> (3); // Works boost::shared_ptr<A> p1 = make_shared<A> (v); // Does not work, there is no conversion from std::shared_ptr to boost::shared_ptr --
Where std::make_shared is used here? Best, Vicente