Re: feedback on supporting libc++

[Josh Durgin <josh.durgin@inktank.com>]

On 10/29/2013 03:51 PM, Noah Watkins wrote:
> Out of the box on OSX Mavericks libc++ [1] is being used as opposed to
> libstdc++. One of the issues is that stuff from tr1 isn't available
> (e.g. std::tr1::shared_ptr), as they have moved to std in c++11.
>
> I'm looking for any feedback on this patch set, or if there is a
> better way forward.
>
> A set of patches on ceph.git:wip-libc++ [2] adds initial support (with
> a couple temporary hacks). These patches are very similar to the
> method used to support libc++ in mongodb.
>
> Summary of changes:
>
>    std::tr1::shared/weak_ptr maps to ceph::shared/weak_ptr

I'm fine with this approach in general, but we need to be careful about
changing librados.h[pp], since that may break the ABI.

We really should've hidden the entire implementation of ObjectIterator
to begin with, but now we're stuck with it in librados.hpp. This branch
changes a std::tr1::shared_ptr there to a ceph::shard_ptr, which looks
unsafe to me. Could you check whether you can run 'rados ls' compiled
against an old librados, but dynamically loading librados from this
branch compiled in c++98 mode?

Josh

>    hash_map/set maps to ceph::unordered_map/set
>
> which will choose tr1::unordered_map/set over ext/hash_map/set.
>
> [1] http://libcxx.llvm.org/
> [2] https://github.com/ceph/ceph/compare/wip-libc%2B%2B