On 9 August 2012 09:35, Paolo Carlini wrote: > > When it does, and the corresponding PR will be *ready* we'll reconsider the > issue. After all the *months and months and months* spent by the LWG adding > and removing members from pair and tweaking everything wrt the containers > and issues *still* popping up (like that with the defaulted copy constructor > vs insert constraining), and with the support for scoped allocators still > missing from our implementation, we are not adding members to std::pair such > easily. Sorry, but personally I'm not available now to further discuss this > specific point.
I'm with Paolo on this. No additional (non-standard) constructors in std::pair please. If it was possible to do without changing the ABI I'd include <tuple> in the unordered containers anyway, when add scoped allocator support, because std::tuple already knows how to avoid the EBO for 'final' allocators (PR 51365). I'd do the same in the other containers except that they need to work in C++03 mode without std::tuple. I think we should consider std::tuple almost as fundamental as std::pair and shouldn't jump through hoops to avoid using it. It's already included by <memory> for example, to implement std::unique_ptr, and I recently made changes to make it easier to use std::unique_ptr internally, so we shouldn't be afraid of std::tuple getting used more widely.
