Thorsten Ottosen <nesotto <at> cs.aau.dk> writes:
Joaquin M Lopez Munoz skrev:
Yep, why can't you just define null guard as
struct null_guard:boost::multi_index::detail::scope_guard_impl_base{};
the ?: operator seem to require that the second argument can be converted to the type of the first argument.
I might be missing something, but I think tou can simply write the following to circumvent the problem: #define BOOST_AUTO_BUFFER_CONSTRUCTOR_SCOPE_GUARD() \ boost::has_nothrow_copy<T>::value ? \ static_cast<boost::multi_index::detail::scope_guard>( \ boost::auto_buffer_detail::null_guard()) : \ static_cast<boost::multi_index::detail::scope_guard>( \ boost::multi_index::detail::make_obj_guard( \ *this, \ &auto_buffer::deallocate, \ buffer_, members_.capacity_ )) Does this work? Additionally, why are you doing the guard selection on run time? boost::has_nothrow_copy<T>::value is a compile-time value so you can select the exact type of the guard (null or otherwise) with some Boost.MPL.
Unrelated to your particular problem, is this auto_buffer class of yours part of Boost or a private project? If the former, we should think about moving scope_guard to boost/detail/ where implementation bits common to several libs inhabit.
That's a good idea. I'm using it for an upcomming library called Boost.AutoBuffer.
I'm confident that other boost libs also use it.
I've just made a global search and the only other lib using it is Signals2, inside a detail component of yours (the one you intend to promote to official lib status, I presume). I'll add this move to boost/detail/ to my todo list. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo