Boost C++ Libraries: Ticket #12003: Implement is_constrructible -- no variadics

cc changed

raad@… — Fri, 19 Feb 2016 02:21:07 GMT

cc raad@… added

akrzemi1 — Fri, 19 Feb 2016 07:34:59 GMT

And possibly define a macro saying if at least two-argument version is implemented, in a form similar to Boost.Config. This way the user could make a decision whether to use the trait or not.

cc changed

marci_r@… — Fri, 19 Feb 2016 20:31:11 GMT

cc marci_r@… added

John Maddock — Sat, 20 Feb 2016 17:47:27 GMT

Which compiler are we talking about here? We really do need a C++11 compiler to implement even a non-variadic version. We could possibly extend it to msvc-12 and gcc-4.4 in a non-variadic form (or possibly there would still be compiler bugs preventing that - I seem to remember the issue with gcc-4.4 was with use of decltype). If you're hoping for a C++03 version then you'll need to supply a PR.

akrzemi1 — Sat, 05 Mar 2016 22:32:36 GMT

Visual Studio for, I think, two releases supported decltype but no variadic templates. I really had this compiler in mind.

Whether this makes sense or not is one question, but the other question remains. It is not strictly in the scope of this library, but could you give me a macro that says if the is_constructible works correctly or falls back to a negative default? Currently I had to repeat the long #if from is_constructible.hpp, as I cannot rely on the 'safe' default.

status changed; resolution set

John Maddock — Fri, 02 Feb 2018 19:26:07 GMT

status new → closed
resolution → fixed

Somewhat better late than never, the macro BOOST_TT_IS_CONSTRUCTIBLE_CONFORMING will now be set when the trait is fully usable.